ok here is the problem, for Christmas my woman bought me 4x new tyres for the tin top, i've only just noticed i need 215 50 17 yet shes bought me 215 55 17, so the new ones are a little taller, is this going to be a massive problem ?

speed will be out a little i assume and the car will sit a bit higher will i notice it only takes me to and from work 15 miles every day?

sending them back is not possible as it would cost to much.

Bung the sizes into a tryre soze comparison (like this, first one I stumbled accross http://tire-size-conversion.com/tyre-size-calculator/ ) reveals a 3% difference. And about 20mm larger diameter. That is about the same as a new tyre compared to one worn bald, so not a lot.

Around a 10mm difference in ride height, which is probably 16mm if you're replacing a bold set of tyres. I wouldn't worry about it too much for the commute. The only legal thing to check is that the speed rating is OK for your car.

Not sure how much the speedo would be out, but I suspect its less than 5% which would be difficult to spot anyway. This is in my opinion and I expect to be blown out of the water by someone with some technical knowledge!

thanks guys, i'll get them shoved on.

The only thing that would worry me, and not wanting to sound pedantic, modifications from standard and your insurance, if that tyre is not listed as a standard spec for your car?

As long as the tyres are safe, insurance wont be interested