Thanks for all of the input everyone. Yesterday I went out for another ride and thought I would double check the pressures... They were 3psi down both front and rear. I put them back up to 36 and it's a different bike. It goes to show how a small change can upset things. I suppose it's two changes what with the different tyre in the first place, but you know what I mean. A little embarrassed after everyone's help, should have bloody checked it rather than relying on the tyre fitter!