Thanks NormK and Mowerfreak

I might give the fiberglass a go, as I don't think I could bend the tin properly.

Exactly Mowerfreak - just getting another base is probably the best alternative. I've quite a few low arch storebrand mowers at the tip shop, some with good bases.
I might just use this base as a learning exercise and give the fiberglass a go.

Regards
Tyler