P2P is really the place to be to get the higher rates, easy to get 10-12% from places like Ablrate, MoneyThing and perhaps SavingStream, thought that is before possible bad debt, none of which has been significant yet for any of those relatively new providers. Just one default at SavingStream that was fully recovered and none yet for the other two. Secured lending, usually with decent security, though some degree of selectivity is desirable and I don't participate in all offers.
Those three places all have lively secondary markets, particularly MoneyThing and SavingStream. Ablrate is active and offers the opportunity to try to sell at above the purchase price. Capital gains on P2P are typically tax exempt as sales of simple debts in the hands of the original owner of the loan. Not enough deal volume a Ablrate to really exploit this hugely but there are other platforms with more volume that I don't use so can't comment on..
No way I'll get an extra 25% on the stoozing because of the 0% for the first £1,000. With more than £6,500 in interest anticipated on over £50k stoozed it's a nice little boost but that's all.
VCT is my main 0% tax tool with the bonus of some tax exempt dividends from the VCT purchases. I might get another 10-12k of interest on top of that stoozed money. That by using a cash ISA with the flexible ISA feature of allowing withdrawing and redepositing of past year money within the same tax year. Transfer S&S to that, withdraw, invest in P2P, exit before end of tax year and redeposit to preserve 100k or so of ISA pot size.
The level of interest is high enough for stoozing fees to be insignificant and even life of balance deals can be significantly profitable.