The best place to do that is localbitcoins.com they provide a peer 2 peer trading service so you can sell to someone paying directly into your bank. It provides an escrow service so you don't release the coins until the money is in your account.
You could also try selling it on this forum but I'd go with localbitcoins myself.
Depending on what amount you want to sell, localbitcoins may not have the liquidity, so you are limited to european exchanges. You can use Kraken, Bitcoin.de, Bitstamp, and any other exchange that will lead to access to SEPA exchanges.
But since GB has declared Independence, im not even sure anymore if SEPA still applies.
But they haven’t separated from the EU yet, so they are still in SEPA. They might even remain there after Brexit, depending on how negotiations go.
Thanks for the input people. Im not looking for the large transactions, i only mine £75 to £120 in a month. Just wanting to sell what ive mined.
I don’t see any point in cashing that unless you desperately need the money. Bear in mind that you might regret cashing it if price goes very high. If you keep accumulating it is good to cash a percentage but always stay invested. Anyway, that’s up to you.