The number of wells at any given time is insignificant really, as Steve Grindlay mentioned to me wells could be dug/filled at will, and that many houses in those days had wells in their gardens.
"At the height of the spa's popularity there may have been as many as a dozen wells clustered near the junction of the present Taylor's Lane and Wells Park Road. Small enclosures were permitted around each, with a cottage to house the proprietor and shelter the water drinkers."

John Rocque's Survey 1741-1745.
One can make out Kirkdale, Westwood Hill and Sydenham Hill, but Wells Park Road probably didn't even exist when this survey was taken during a time when the mineral spring site was in it's heyday. The number of wells is not so important, but how many cottages were there? Depending on the accuracy of the survey, there appears to be 7 cottages standing in a circle during this period. Buildings around Peak Hill (oldest in upper sydenham; see [this] topic...), south of Westwood Hill and Sydenham Road are shown. Based on the previous quote above and this survey, is it safe to assume there were more cottages when the wells were more popular?
"By the nineteenth century the fame of the wells had declined. In 1878 Mayow Wynell Adams remembered the remaining well as being 'but a dirty pool and water very nasty' and commented that the wells had been filled in."

First Ordinance Survey Map (1799).
The Croydon Canal and Sydenham Reservoir had not yet been dug out. Only 4 cottages remain and can be made out on the map (two either side of Wells Park Road including one set back a bit towards Sydenham Hill). Note: The junction with Kirkdale was different in those days; instead of curling around to the north, it passed eastwards straight across Jews Walk and joined up with Peak Hill.

Enclosure Award Map (1812)
The same 4 cottages can be seen in this map (circled in red). Taylors Lane has now been laid out all the way south to Westwood Hill from Wells Park Road, in-between two of the cottages on that side of the road. There is also a lane/path leading to the cottage off the beaten track.
The 4 cottages were as follows:

Two cottages on the south side of Wells Park Road with gardens and a thinner Taylors Lane than the road today, running in-between. When this illustration was drawn, some more buildings had started to appear on the right.
From right to left:

1) Wells Cottage (double roof).


2) "The Wells" (evidently rebuilt).
North side of Wells Park Road:




3) The Green Dragon (rebuilt in the 1800s then destroyed by a V1 in 1944).
King George III stayed at the Green Dragon and drank from a well in the garden. In the first illustration, could that be a bridge over a well before it was filled in? One well was supposed to be beneath the front of St. Philip's Church before it was built in the 1860s. People describe staying at the Wells Cottage and Green Dragon to drink from the wells, hoping to be cured of illnesses, but there is no mention of the 2 streams that ran through the fields that were later to become Wells Park (the streams joined into one down the middle of Taylor's Lane; see [this] topic). I assume these streams were entirely separate from the dozen or so wells?
"Nowadays, to remind householders of their ancient history, water pouring out from the springs still gives problems, flooding cellars and basements."
But this is due to the streams, not the wells?
"A physician, John Peter, had commented in his Treatise on Lewisham Waters in 1681 that at 'the very place where now the wells are, there used to be only the gushings of water, where multitudes of pegeons used to frquent; enough to give intelligence to any observing naturalist love to be tippling'."
Is this a reference to the stream(s)?

4) Rose Retreat (old cottage pictured with a newer building beside it).

1843 Tithe Map
By the 1840s, Springfield Rise and Mill Lane had been laid out (see [this] and [this] topic respectively). New buildings had started appearing beside Wells Cottage, branching around the corner onto Wells Park Road. One of these buildings opened as the Gardener's Arms pub, which closed in about 1912. I've not seen a full on picture of this pub or parade, but Steve Grindlay said he might have seen one.
The surviving Taylors Lane cottage had been built (see [this] topic). Two unknown buildings appeared on the plot to the right. Not sure what was happening at the top and bottom of Wells Park Road (not enough coverage on the map), but 90% of other new buildings that appeared along Wells Park Road can be seen in the painting of Jews Walk (see [this] topic). Building (9) has a distinctive chimney beside it.


Red (05) = Blue (05)
Red (06) = Blue (07)
Red (07) = Blue (08 )
Red (08 )= Blue (10)
Red (09) = Blue (11)
Red (10) = Blue (12)
Group (6) on the 1843 Tithe Map had not been built when this picture was painted in the 1830s, but the 3rd building on the right of the group (opposite Mill Lane) was to become the Cottage of Content pub (see [this] topic) in 1850.
Going by a later map, Group (9) and (10) on the Tithe Map appear to be Prospect Place (see [this] topic), part of which can be seen in the painting, but some of these buildings were possibly altered before the next map was published...

1849 drainage map
The first half of Halifax Street has now been laid out with some cottages each side (must be the oldest surviving ones up the road), along with two or three more newly built cottages on the north side of Wells Park Road nearby. A nice space has been reserved on the west corner of Halifax street for a chapel built the following year after this map was published. More buildings have started to appear east of group (6) and the pub.
Halifax street (see [this] topic) was originally planned to meet Kirkdale at the first bend towards the Denham Court site (see [this] topic), but was changed to come out in-between the Post Office and Woodman (see [this] topic). Thanks to Steve for this info.
Rose Retreat now consists of 3 buildings (might all appear on the Tithe map as well).
The building with the chimney has been replaced with the Beehive pub.
Some buildings have appeared at the junction with Kirkdale. One of these must be the surviving Farnboro house, dating from around 1840, so it may be on the earlier Tithe map as well--same with the Fox & Hounds pub.

Farnboro house.
This is where it gets difficult, so I'll continue this evolution of Wells Park Road another time... Any additions/corrections so far please let me know!
EDIT: Spelling/Grammar