Don't make it a secret!
Anyway, knew you wouldn't know the answer to the other question... they introduced one piece tubes a couple of years ago, but only standard for the larger RIBs (9m+) if I remember correctly, which of course, I may not! (accordong to you)
The thing here is that you're not comparing like for like. The fact that you paid £xxx.00 for a hull + tubes from Humber back in 2003 has foxtrot uniform charlie kilo all to do with the fact that matey paid £yyy.00 to have the tubes removed, then new ones made and fitted to his RIB five years later.
What I would be interested to hear is how much others have paid for retubes from reputable sources?