My Leisure Battery Tray is too small :-( Replacement help?

[Observer]

Here I was about to buy a new 110Ah Platinum LB when I thought, 'hmmm, I should probably measure the LB tray I have'...

So turns out it's not very big. From the photos can anyone tell me if this is the standard Mazda near side (2nd battery) tray ?

Existing Dimensions L/W/H
85Ah Leisure Battery: 250x170x210 (at back and 185 at front, the terminals are in a recess)
Tray looks to accommodate: 270x170x190ish

I'm hoping I can just unbolt this thing and pull it out. I've been reading that Willinton supplies a large tray that can take a 110, can anyone advise if that would bolt into this space once this ones out? I've got some tools but no workshop, tho if it's not too tricky I'm sure I can do it. I don't think I can make my own tray and bracket.

I followed all of this, purchased and fitted the new LB and it's all working good. My question is, now that it's getting colder I can't see the Mrs wanting to go off for many weekends so what is the best way to maintain the new battery? Should I leave it in the Bongo or remove it and leave it on trickle with a Lidl Ctech-alike charger throughout the winter?

[g8dhe]

Leave it on trickle charge, we just plug our vehicle in at home every few days or if we know we aren't going to use it for a few days.