I am unsure if the colour matters, if that means a different variety ?

I found some more, but in a completely different location. Whilst they have a similar cammo design, albeit a different hue, it struck me that as they blossom that hue lightens, which seems to be the reverse of say how tomatoes behave, as they deepen in hue the longer they're left to mature ?

It's definitely a lilac, but as there are probably thousands of different cultivars, it'll be hard to get an exact name. If it's at a botanical garden or similar, they usually keep charts of what exactly is planted where, you might try calling and asking. Even a home owner might know what they planted.

This was on hospital grounds and they have other priorities, so I think it a wasted errand.

Lilac you say, does that still classify it as a Syringa ?

Syringa Vulgaris is the scientific name for common lilacs. There are others in the shapes of trees, but pretty sure they all start with Syringa.

This is the first page of the Lilac database, the list starts with the various species and then goes into the named cultivars.
https://garden.org/plants/brow...

S. pubescens is one species and the blooms and fragrance are different than the common varieties.
This one is mine.

I find it too difficult to understand the database, so many of the flowers look identical.

It is not only about the flowers.
You need to look carefully at the leaves.

Pics below show .... Syringa meyeri palibin..leaves are small, roundish.