Took me longer than it might've to look at this one because I'm feeling a bit saturated with "city centre" mystery caches: why are there so many these days? Pub quiz questions were right up my alley and it was only having forgotten about the existence of a particular piece of filming history that slowed me down - luckily I was able to derive from the maths where my error was likely to be and correct it, and geochecker confirmed where I was headed.
The first place I searched gave me a false sense of satisfaction when I felt something small and smooth stuck-on to something near the GZ... but it turned out to be a snail.
The second place a searched resulted in a knuckle full of stinging nettles. Ouch!
But the third place I searched put the cache right into my hand. Delightful.