In response to KR’s request I have added some more photos of a Bb set composite with parts by Egan, Colgan and at least one other. The instrument has had a hard life and several of the parts have been rebuilt, not necessarily in the most professional manner.
http://www.bagpipeworld.co.uk/Gallery/EganBig.htm
It has a number of unusual features including a Bass regulator that plugs into the main stock and has an internal crook plus the large Double Bass Regulator that is folded back on itself and has a couple of keys alongside the main stock.

There is a sketch of a similar instrument being played by Capt. Kelly in IMM - I have seen a copy of the original oil painting from which this was probably taken and D Bass is clearly visible with the loop end.
I am currently working on drawings for this instrument at the moment - for the position regarding the future of these please contact me directly.
Note please that I will be away on holiday so it may take a couple of weeks before I can get a reply off
and … Mr Rietmann - please check your private messages
Cheers for now
Chris