Doesn't moneysupermarket have a early repayment filter so you can choose those with or without early repayments?
There do seem to be a lot of factors, cashback, repayment charges, the rate, term, various types, etc. It can take ages to work out exactly which is best!
Not sure if you have significant savings but the offset mortgages can be good in this case as you only pay interest on the amount greater than the sum of your savings if these accounts are through the same bank. Also, you don't pay any tax on your savings because you are forgoing the savings interest to offset the mortgage. I'm going to investigate this further when our fixed rate term ends next autumn.