Burford second battery

Hi everybody just wondered if any has fitted a second leisure battery to a burford or any other Merc 
Is there room for it under the passengers seat base or do I need to mount under van ?
Understand how to connect up the two batteries and I will probably buy two new ones the same and will reset battery size in menu in control panel but is there anything else I need to address , is the mains charger and alternator big enough
Thanks for your assistance I have looked on  the forum here but couldn’t find the answers

Previously posted by Peter Brown for a Burford, should be the same for Bourton. In tghis thread https://www.autosleeper-ownersforum.com/t28930-bourton-leisure-battery#241580

Hi
   We have a Gloucester (Merc) and that has 2 leisure batteries ,one under the front seat and one under the rear bed
Alan

Hi yes it is possible to fit 2 batteries under the passenger seat. We have just fitted new ones and easily got in 110 amp hour batteries
Make sure you use AGM or lithium type however
Geoff