I have tried intersango but nobody was buying bitcoins
It is an order book, .. there's always bids, thus there's always someone buying bitcoins. Did you mean to say the bids were better on Mt. Gox so that's where you sold?
small amount of cash, 20gbp, that i hold in mtgox
There is a $75 recommended minimum for International Wire withdrawal, I think that's because the fees make anything less cost prohibitive.
It doesn't look like under the new Withdraw Center that there is an option to do a domestic GBP bank withdrawal so for bank transfer the International Wire looks to be the only option for that.
i would like to know is if there is any other way to get my hands on my money?
Could you instead accept PayPal withdrawal?
Bitcoin Nordic and Spend Bitcoins both offer a PayPal cash out service. (You'ld need to do a trade in Mt. Gox to buy back bitcoins using your GBPs first, sorry).
You might also try doing a trade in the #bitcoin-otc marketplace. There are P2P services, like Barclay's PingIT which you could use to receive a GBP payment in exchange for your GBP Mt. Gox redeemable code. You could probably find someone willing to do that 1:1 (i.e., no fee). Do check their trust history on the #bitcoin-otc Web of Trust (WoT) first. Redeemable codes are useful for escrow so consider using a trusted escrow partner if you have any doubts that the counterparty can be trusted.