It's one thing to buy an old rib that's been well maintained that you can tinker with and revive the tubes with a thorough scrub, but that looks like a pointless project.
As mentioned, PVC is fine if it's been maintained up to a point, but that old Bombard looks in a sorry state. If the tubes are starting to degrade, And glued seams are suspect, then you're looking at minimum of £1k per metre to retube.
You'd be better off with a hypalon tubed RIB, deeper V hull. Worst case scenario, if you've bitten off more than you can chew there's always a ready market looking to buy back.