We do notify the credit card company every time before leaving the US for the UK to avoid the credit card being blocked while in the UK.    We also do not ever use an ATM .   Question however has to do with ordinary businesses--restaurants, gift shops etc--who do take Visa.   Will they usually take a Visa without a chip/PIN or is that dying out?

I think that's the main question posed by the OP, and it's a good one.