Problem solved, I bit the bullet and bought the upgrade kit from Bedford Saw, £78 delivered.
Not expensive considering the amount of machining on the blocks and all the bits and pieces included, you even get a new slidey up and down thingy.
Bit fiddley to fit especially with my sausage fingers and quite east to set up and it does cut better than with the original blade guides.
I would highly recommend this kit if anyone else is thinking of replacing the original guides.