mo wrote:
B and Q? Or will I have to look more local?

All the floorboards in my room are different sizes - I guess I will
have to give them exact measurements? (width, height and thickness?)
and they can cut them to order?

Is there a cheap material you can buy to put on top of floorboards to
make the floor totally flat?

I would suggest a local builders yard or wood yard.
B&Q are expensive when it comes to wood and I have found wood is cheaper at
the wood yard,thats locally by me though.