Most Scott radiators that have 3 bolt fixings have a marked restriction to water flow around the single lower bolt fixing. The position of this bolt in the core is important.Many are very low which just exasperates the problem.The potential problem can clearly be seen when you look inside the matrix via the bottom outlet.It is also possible that this area is blocked with debris etc. It may be worth unsoldering this bit of the rad and sorting it out.
I have always had radiators built with only 2 top mounts. I also leave at least a quarter inchspace under the bottom row of tubes (a sort of collection area). These radiators have about twice theflow when compared with a std one and I have never had a boiling problem, either on the race track or road. Having said that, std radiators normally only give a boiling problem either under prolonged slow running or continuous high speeds (65mph plus).
Both honeycomb and later rads seem to perform equally badly if the bottom mount is restricting the flow. Ian Pearce fits an expansion tank to his Brum road bike, allowing the excess water produced from boiling to be sucked back into the rad upon cooling. His racing bikes have special one off rads.
Give me a call if you wish to discuss 01628 891507(home evenings)01494 887569 (work)