Leisure Battery for Peugot Boxer Symbol

Dear fellow campervanners,
My leisure battery was running hot so disconnected luckily since it was subsequently diagnosed as dead and could have caught fire !! I bought a leisure battery from Halford's online but when I pitched to have it fitted they said they did not provide a fitting service. I think Kwik Fit will do the job but I have to source the battery. I have a small solar panel and MPPT unit which tops up the leisure battery I also have a 700W inverter which I use to run the Cool Box.
My question. How do I know what size I need and secondly which battery would you recommend? 
Thanks and regards
Chantal

If your battery is under your drivers seat you won't be able to get anything bigger than you already have , so stick to same size, type number should be labelled on it such as 019 . Measure yours and check Tayna website , dimensions are given to all their batteries.

Dear Paul,
Many thanks for your excellent advice. Once I've identified the battery required I'll probably fit it myself as I have an MPPT for my solar panel.
Any thoughts on how much drain would come off the battery if I ran my cool box off the 700w inverter I've installed.It will depend of course on how long I use the inverter but maybe switch it off every 4 hours to let it recover.
PS If I'm on an electrical hook up will that power up my leisure battery.
Best regards 
Kevin ( Chantal's hubby)

I've no experience of inverters. When on hook up your leisure battery should charge and all your 12 v appliances will run off the charger.

Thanks Paul
Regards
Kevin