If I was going to look for repair panels I'd go to rimmerbros.co.uk and search for mg zs or rover parts. They sell many panels.
Altho unsure of a particular section like that.
Usually I'd say of you can find a good welder rather than just enough to get through the mot kinda guy.
Should be able to do a decent repair. I can recommend dynodaze he repairs many old jap cars to a very high standard. Located Nuneaton. My be to far for you though.