I have just ordered one of the AGM batteries recommended by Roy (thanks Roy!) - my car is already setup for the polarity.
I did think of getting a main brand (Bosch, Hella...) "normal" battery, which of course is cheaper, but then some places couldn't tell me if it was in stock unless I ordered, and others more honestly said "not in stock". Others again did have it in stock, but then wanted ££ for delivery, and also some surcharge to be reimbursed if one returned the old one ...
all very complicated and cumbersome.
https://www.batterymegastore.co.uk/ however has the Optima 'yellow top' YTS 2.7 AGM batteri at £139, with free next day delivery, in stock.
That was a lot easier, and already well worth the extra expense :-)
460 CCA should be good :-)