There is death and injury for hedgehogs in bonfires built in advance of lighting. There is advice on how to minimise this here:
(I couldn't find a relevant category so I am hoping it is ok to post this here)
ah very good advice for people- poor hedgehogs
I suspect that this generally good advice is largely irrelevant for Harringay gardens but I should be interested to know whether anyone has seen a hedgehog either alive or dead in this area.
In the 20 years I have worked my garden (1979-1990 and 2007-date) I have only once encountered a hedgehog. That was 30 years ago when I found a pair of dead ones that had crawled under a boiler - presumably for warmth - and died there.
The attached link suggest that they are very uncommon. Perhaps in Finsbury Park?