Some parts may have to be new for safety, like the petrol tank, unless Thumper has a good one somewhere. Water tank again, possibly better remade. Try MetalFabs in Corby for both and ask for Mark on 01536 202448, they are brilliant.
A screen can be remade from new if it is pastic by Littleport Boat Haven in Cambridgeshire, 01353 863763, ask for Gary. Sometimes he has the mould or similar, however if he has to make a mould (which he did for me), it hurts a bit on the pocket, but worth it eventually. Maverick was lucky, Gary had a mould for his boat and I think it was very reasonable.
The rest can all be sourced, just takes a bit of gathering together. Down side, restoration is never going to get your money back, but boy the satisfaction when you finish and use the boat.
Below is my Albatross, which is now having a new petrol tank fitted and a few changes. I have the original steering wheel, but it is too big for comfort, so a cheapy is added for comfort.