I was in Ukraine last weekend and came across an interesting DCC example at a PrivatBank (ПриватБанк) ATM.

Put my GBP debit card in the machine, asked to withdraw a few thousand UAH. Offered DCC, as expected. But it was changing it to EUR, not GBP. So my bank would still have to do a conversion. Rejected this and was offered it again. Refused a second time, next screen informs me there is a 150 UAH (~£4.25) fee for no-conversion. So I cancel transaction.

Another nearby ATM (IdeaBank) offered no DCC and had no charge - just the way I like it.

Otherwise I used a GBP credit card in bars, cafes, restaurants and shops seeing no DCC anywhere. Contactless and phone payments are very widely accepted, with some more expensive stores preferring it to cash.