If your in the England, don't bother !! most traditional English style fiddling used little or no vibrato !!

I'm in England and we play an eclectic mixture of traditional styles at the sessions I go to. There are several delightful waltzes and slow airs that benefit from the judicious use of vibrato. My vibrato technique is such that I normally switch from the fiddle to the mandolin when we play those tunes. Just because I can get away without vibrato for most of the time, is no reason why I shouldn't stretch my technique to include something that adds warmth and colour when used at the right time.

DC