you’d have to stack 3 maybe 4 wall units to make a full height larder cupboard, not necessarily a bad thing but you would obviously see they are stacked and may not like the joins showing. Plus that’s a lot of cutting out to do, which you’d be better spent with my previous suggestion.. I reckon you could do it with
4 x bits of 4×2 at 2.4m
1 x End panel (stripped to fit required depth)
Bit of beading/caulking where the door meets
1 or 2 x Larder doors
Hinges – (recess the hinges into the 4×2 – of run a strip of 18mm ply on whatever side you want the doors hung instead of the 4×2 and hang doors form that
Dozen rawl plugs
80mm screws
Jobs a goodun.
make sure there is some ventilation for the boiler as I think you can void warranties if you don’t.
If you got down to a Howdens clearance centre (or other), you could have all this done for under £100 easy..