Can Bottom Bracket be re-tapped at any bike shop and how much would it cost

A good shop will have BB taps, i'm running a set through a bare frame tomorrow for £10ish. Worth bearing in mind that you can't re-tap into nothing, so if your threads have been totally destroyed then you'll need a proper repair/replacement shell from a framebuilder such as argos racing cycles.

I had an Italian BB sleeved & tapped once. Cost about £25 but it was about 18yrs ago. Yes, I'm old.

You can also buy BB's that don't use threads a mate of mine has one in his SS bike as he did the same thing, a company called Acor used to do a square taper one.

Mananged to get it Chased at LBS. They did a good job for £20 – I thought I might have totalled it