Thank you for your replies, there is a lot of food for thought there.
Like Parsonage Bees, I was enthused by Mike Palmer's system of running continuous nuc colonies to support production colonies and also to produce new colonies or saleable nucs.
I picked up a copy of EB Wedmore's A Manual of Beekeeping, first published in 1932, it describes shared brood boxes with oposing entrances so as Mr Palmer says in his talks, it's not new.
I am just surprised that I can't seem to find the two half sized boxes that would fit side by side over a brood box.
I don't have the facilities to make my own at the moment, which seems to be the way forward. I like the look of Joelsoo and Parsonage's boxes.
I'm looking at plans for my future retirement, which I intend to involve a lot more bees, hence wanting costs to make a reasonable business plan.
Looks like I may need a carpentery course and a some tools to invest in if I want to try the Palmer method.
Alternatively maybe just stick with standard nuc boxes if our climate doesn't justify the need for shared heat.
On that note, do any of the poly nucs have supers or extra brood boxes on top?
I have a Maisemore six frame national nuc that I bought from Abelo, I'll have to look into that as an alternative.
I have Abelo national polyhives that I really like, their crown board seems made for putting nuc boxes on top but Abelo don't seem to do anything that will fit on top, surprisingly.
Running plenty of nucs still seems a good idea to support a large apiary.
Thanks
Courty