Well you have to have £20k at the lower tax rate and £10k at the higher rate in a 5% account to get to the amount you’d need to declare. But really that first £20k should be in an ISA, so really you have £40k/£30k (double if you have an accommodating wife) Then it goes into PB’s. That’s a fair amount of savings for the average person.
On that note I’ve always wondered how invested monies work – say you have a non isa/SIPP Vanguard account and it’s made money, I assume it’s not declared until you withdraw it? Becuase of course it could go down again, so technically you haven’t made money until it’s withdrawn….