Fitting sub board or bigger CU for solar PV/EV?

whosedaddy?

Hi. I currently have a 36 module , 2 row fix-o-rail surface mounted CU with 2 free slots (wires fed in through the back ) - house was rewired 5 years ago.
I’m looking at putting in solar PV (and EV charger down the line) and need few extra slots.
As the top of CU is at 2.06m and with regs saying max height is 2.15m for highest device, I don’t think I can put sub board above.
(At least I haven’t seen any single row CU/DB that might fit the profile).
There is some slack from what I know to move down 2 inches to allow fitting above.
Or alternatively, what would be involved replacing the 2 row CU with a 3 row one ? Keeping the bottom 2 being same place as they are now?
I can’t fit sub board left or right of the existing CU due to immovable obstacles.
Replacing CU is guaranteed to work, but probably by far the most expensive. Any ideas re sourcing a slim sub board?

Edit: I’m not planning on doing this myself, but understand options , so I can start planning the PV project .