Thank you to everyone for your opinions and ideas.
I removed part of the plasterboard on the wall where the CU has to be fitted. It is a bearing wall with space of 320mm in between the studs, I expected to have a bit of luck and get at least 360mm to get a normal CU but I wasn't lucky this time.The space in between plasterboard is 85mm.
I have been searching for the right size of box but I can''t find any Dual RCD box to fit there with a minimum of 7 MCBs.
I would love to get a Design 10 Flush Consumer Unit by Hager with 10 ways and get the main switch plus 8 RCBOs but we are talking of over £250 and It doesn't give much room for future upgrades.
Also I have seen a Wylex one which I could fit removing the plasterboard on the back and fitting a new solid wood board on the top of the plaster (screwing to the timber, of course) to make the wall 12mm deeper. It shouldn't be to difficult.
Wylex Metal 17th Edition Amendment 3 7W High Integrity + 7 MCBs Consumer Unit - Toolstation - https://www.toolstation.com/shop/Electrical/d190/Wylex+Consumer+Units/sd2615/Wylex+Metal+17th+Edition+Amendment+3+7W+High+Integrity+%2B+7+MCBs+Consumer+Unit/p67344
I could take out an RCD and fit individual RCBOs to get extra space from a "two way" RCD ending with:
11 SPACE
RCD 1
32A Socket Ring Main
6A Smoke Detector and Lights
16A Immersion heater - in case the gas boiler fails
6A Gas Boiler
RCBO
32A Induction Hob
32A Separate Oven
32A Kitchen Ring Main
16A Outside Sockets
40A Electric Shower
What do you think about this idea? Also do you think I could combine any anything to save space in the CU?
Again, Thank you very much for all your help