the saw is a perfomance pro ( the blue one) that b and q used to sell, i know not the best but i have tinkered with it and blade is now square to the top. i think they replacd it by macallistair ones but they are the same from what i gather minus the router insert in the top.
pretty sure the riving knife would match the 2.8mm, It's made from a proper piece of steel and its chamfered at the front ( ie by the blade).
received the 40T Freud blade and the difference from the old blade is staggering, cross cuts are as smooth as i ever seen. I would have never thought a blade could make such a difference.
Also tried a rip cut through 12mm thick stock and again amazed how clean the cut was.
@£22 for the blade its a bargain.
thanks everyone for pointing me in the right direction.