I'd probably go with premium bonds too. It needs to be cash or PBs, and the return on both will mostly likely be very little, but that's not the point, you need some ready cash available for broken boiler, car repairs, etc etc.
Plus with PBs, it's a bit more faffy getting your money back, you have to request it and it takes a few days. If you have a credit card with a decent limit, you could always pay for your emergency on a credit card and then use the PB money to pay the credit card off when the bill comes.
The most you can get with a savings account is 0.5% or less than £20 per year.
Statistically you'll win maybe once a year with PBs. There's a good chance you'll win nothing or maybe one or two prizes in a few years. Of course you could win more.
So if you're comfortable gambling a guaranteed £17.50 in interest each year, with the added bonus of putting a small hurdle in front of 'accidentally' spending your savings on an 'emergency' holiday chance would be a fine thing then there's your answer.
As it happens, I've given up with regular savings accounts, after running a couple a year for the last five years, because I worked out that, even by putting the maximum amount allowed in the best paying account, you get about £15 a year in interest and I couldn't be arsed setting it up, tying the money up and then dealing with the uncertainty about what happens at the end - one bank I use automatically lets it run for years and years, the other you have to reapply and I could never remember what was going to happen.