The new battery arrived today from Tanya, £99 delivered. This one:
https://www.tayna.co.uk/610-200-Vart...92--P3200.html
Fitted it up no problem, case was identical size/shape to the OEM and ratings all within a few percent too. Car started and runs normally, all electrics work normally too, its as though nothing ever happened. So far so good
Thanks for all the advice on this thread.