Right. Sorted. Squeezed out the liquid from the blocks, chopped up, and dry-fried as per, for example, spinach. Then popped in 40 g or so for the curry.

Tasted OK, but not as good as fresh. The main problem, however, was the stems (this brand of frozen block includes lots of stems, not just the leaves) were not cooked properly. It was like eating a curry full of twigs. So I ate what I could and the rest went in the bin.
When I made this dish earlier with fresh methi I only used the leaves (read somewhere it's just the leaves that should be used). I think I also read somewhere that methi (fresh) should be blanched in boiling water before use, to reduce any bitterness. Can't say I've ever noticed any bitterness using fresh, or dried, providing it's cooked properly; the latter just tastes really "earthy" I think), but boiling the frozen stuff perhaps may have softened the stems up.
Think I'll stick with fresh in future for the methi chicken. It's a lovely dish. For lamb I'll stick with dried, i.e, for a methi gosht.
Rob