An acquaintance of mine keeps Indian Runner Ducks in Peckham. He has a large garden so is able to put up a relatively fox-free run. Foxes will be your main problem over cats. Also, vet in Highshore Road is good with birds.
Lidl in Peckham currently have on sale angora long johns and vests, also skiing gloves, hats and socks (in different parts of the store). This would be a cheap option for you but they change stock quite quickly.
The outdoor skating rinks are fun. I've been to Greenwich and the one in the Aldwych (M House??) - both are fun and very festive. I think there is also one at the Tower of London.