If I have BCH in a wallet whats the quickest way to convert to to BTC or GBP?

Is there a localbitcoins style site for BCH yet?

And even if all that were possible, none of it changes the fact that if bitcoin’s primary use is for speculation rather than transaction, the energy wastage serves very little constructive social purpose at all.

...
Our goal has always been a smooth upgrade for Bitcoin.  Although we
strongly believe in the need for a larger blocksize, there is something we
believe is even more important: keeping the community together.
Unfortunately, it is clear that we have not built sufficient consensus for
a clean blocksize upgrade at this time. Continuing on the current path
could divide the community and be a setback to Bitcoin’s growth. This was
never the goal of Segwit2x.
...