My fixed tariff also finishes at the end of July @
McCoosie. In my case I'm only being offered a 1 year fixed tariff, not a 2 year option like you, but I'm leaning towards the variable tariff.
If I was presented with the same prices as you, then I'd look at it like this:
The variable is £60 per month cheaper and you'll probably get that for 3 months before the cap is increased, so that's £180.
If they were to increase the cap by 30% in October, the variable would still be about £12 a month cheaper, but then there's the next 6 month review after that etc.
My logic would be that you would be saving money on the variable tariff until next March at least, and if the variable was increased again next March, what you've saved by being on the variable would mean you're unlikely to lose out until at least this time next year. What the fixed tariffs would look like then though who only knows.
I reckon that the 24 month fixed option is nearly 8% more expensive than the 12 month tariff I'm being offered, so you have to ask yourself if you think prices are going to continually rise for 2 years.
It's a gamble, but with a £60 per month difference I think I'd go for the variable.