An equestrian statue - the metal is black so it absorbs heat from the sun and warms up a few degrees compared to the surroundings
Fountain - the water in the jet is slightly warmer than the water in the pool, I think it gets warmed by being pumped and by friction with the air. Like an idiot I forgot to take temperature readings, which would have been interesting.
South side of the Albert Memorial - the bits in direct sunlight are mostly the brightest yellow. The figure of Prince Albert is blue / cold, presumably because it's gilded and reflects heat instead of absorbing it.
And the Albert Hall - I don't think it's in use at present due to covid, but they presumably heat it to stop pipes freezing etc.
The rest of the thermal images I've taken so far are here: