As observed before, it seems the bees like variety in their pollen collections and I had seen grey, almost white, beige, yellow and black since the bees took up residence some 4 weeks ago. Today I spotted a bright orange pollen amongst the white and beige. Not sure whether I can upload video without paying for an upgrade so I’ll try to find a still picture showing some. From what I can find out it might be from field scabious.
The fact the pollen is a similar colour to the thread to the left of the opening is a coincidence. for those who are wondering – the piece of material rolled up and blocking part of the reduced entrance was placed there so my (small at the time) colony of bees could defend their stores against wasps. Reducing the entrance allows the guard bees to concentrate on protecting that area.