Thanks for the replies. The problem on the vise suggestion is I don't really have a work shop or a vise, so that might be a problem. I definitely don't want to ruin my frame as it's a good existing example of a classic. I might just start looking at hiring someone as was suggested. I'll start shopping for that and see what I come up with.

Hopefully there will be more suggestions voiced.

PS: I do like the ammonia suggestion.