At this juncture the bronze fittings is academic as that hose is already 'you beaut no smell'.
For reasons I am yet to understand the hose from the through hull is broken in the middle and has a joiner piece then another length of hose to the pump. The hoses I have removed go from the head to the pump, pump to the pop off, pop off to the joiner.
Tried heat, sat the hose end in boiling water for what I would have thought was a reasonable period of time , didn't seem to help cos it doesn't soften the reinforcing.
I've now got the whole assembly in the workshop and maybe with better equipment to hold the hose, things will improve. Will try heat and detergent, maybe heat and silicon. Brute force is of course not to be dismissed.
Hamish' suggestion re the 'barbed' fittings does make sense, cos it was the 'barb' that was giving me the most grief.
“Life is a trick, and you get one chance to learn it.”
― Terry Pratchett, Nation