in direct connection there will certainly not be any impact at all on Bitcoin or crypto widely, but if talking about indirect connection is rather difficult because it covers very many aspects involved here, but it cannot be denied that regulation makes Brexit a comfortable home for crypto users.
A small country like the UK can't have a big impact on something which runs all around the world (e.g. internet, bitcoin, ...).
in terms of size, the area is relatively small if you compare it to China but in terms of economic strength, the UK cannot be underestimated, especially with the power of Commonwealth.