A recommend for Royalex
A good rubbing with some paraffin wax won't hurt the vinyl outer layer but will infuse some depth to the colour of your boat, while also helping to combat drag.
(in my case I need to clean it first!)
Does that mean, it will make my GREEN Canoe go even faster ??.
Mind you, like you Jammy got to get a lot of the DEE, WEAVER, and TRENT off and out of it first, but will deffo give it ago, where do I get the stuff from please.
Regards Bill
Another thing worth checking is all the nut's and bolt's on your seats and thwarts making sure they are tight and inspect for any damage to the woodwork
Aerospace 303 is good for cleaning boats as well.
Another top tip

I agree about checking nuts and bolts, I had a screw fall out of the footpeg bracket up the pool second trip out in the Shaman, and it is a right pain trying to get 10-24 X 3/4" UNC stainless set screws. Got some now but took a lot of hunting to get the right ones.