Being desperate for quick returns is what mostly lead to lose of funds, what you are looking for is possible in a short time in any coin but the fact is it is hard to say which cryptocurrency will give you such quick turnover and crypto markets are unpredictable. So you just have to take the risk and wait to see the outcome.
It will be very hard to be achieved in this bearish trend. The only possible thing for the coin to go down and almost all of the coins already surpassed their old all-time high. Im thinking of OP should go for the something new.
Making 2x return is very hard to be achieved right now, dude. Even when you are using major coins as an investment and you will get nothing.
The only chance to bet on the shitcoin but this is a high-risk high return.
In this bearish trend, @OP can buy bitcoin for £7k, and the rest of the money to invest in altcoins such as ethereum, bnb, litecoin, and many more.
He needs to determine the money that he will use to invest in altcoin because he has so many altcoins that can increase later and not just for 2x or 3x.
With doing research, I am sure he will find the coin and start to buy before the price rises again.
But if he only needs two coins, I think buying bitcoin and ethereum will be enough right now as bitcoin and ethereum are at a low price.