have decided it's worth repairing as the speed tubes are the only dodgy bit, worst comes to the worst I can cut them off and have a normal sib!
Progress so far
Speed tubes - As mine are the non-removable ones replacement wasn't an option due to cost. My solution was to purchase about £30 worth of foam sleeping mats with I then cut into small pieces. Cut a hole in the end of the speed tubes and with the help of some drain rods stuffed the foam into the tubes! You must make sure you get it right to the end. Also make sure it's closed cell foam. Stitched the tubes with fishing line and patched over. They will not be waterproof so I will put a drain hole at the rear. They are very firm and the foam returns to shape when compressed.
Three patches applied to the floor and sponsons, front towing eye reglued after cleaning with MEK, scouring pad (green) and a blunt knife, took forever!!
The two front sections of the floor needed replacing as they have rotted, painted the new ply with ronseal floor paint.
Replaced one valve inner on the the front sponson, easy to do with a pair of long nosed pliers, DO NOT waste money on the valve removal tool!
Sponsons have retained pressure for about 2 weeks now so fingers crossed!!
Hoping to refit floor today so if anyone has the instructions I would be grateful.
Have piccys from day 1 so will try and load them at some stage.
The forum has been invaluable for help so ta a lot