Rafter, you don't need to choose between just the bank retail products using derivatives, and shares. There's a
broad range of funds available that have yields (interest or dividends or a mixture) in the 6-8% range
that can be held tax free within a S&S ISA. As usual with investments the capital value varies over time. Don't just pick the ones with the highest yields.
There's also the Retail Bond Market of the London Stock Exchange where companies can offer bonds for consumers to buy them directly, typically paying 5-7% interest. These are corporate bonds, not term deposit accounts, and as usual for investments including P2P the capital is at risk if the company fails. Not that it's particularly likely for some of them. FSA regulated.
For those who don't mind funding onshore wind or solar there are
debentures available that lock in money for 20-25 years and pay 6-8% in dividends
, split to pay twice a year. Because the payments are dividends there's no extra tax to pay for a basic rate tax payer and just the usual extra for higher rate that takes the total tax to pay to less than the income tax rate. Not that this really is a 20-25 year lock in, while it's possible that there will be a way to resell, don't count on it. FSA regulated.
One of the problems with P2P is that it attracts people who don't know about their other investment options and might miss the safer alternatives that are out there.
As always, I've just mentioned some possible investments and it's up to the individual to determine what is or isn't appropriate for them, if any of them are.