Sorry for delay in updating you on this but mechanic only back in business today after illness.
After careful examination and removal of one of the old Shock absorbers he believes that the low angle required on the 1992 chassis, about 25 degrees, will not make the ALKO green shock absorbers function appropriately and that the fixings even with brackets won't fit!! Will keep you informed over the coming weeks.
Next will go to caravan dealer to see if they can find suitable replacements, if not our mechanic will make further investigations through his motor trade contacts.