I have painted the loft!
Reason being was, I used to house my hawk in there (I no longer have him so don't panic!) and on a weekly basis, I used to go in there with a jet wash and spray it all down. The untreated wood had a plastic coating on so it was easy for me to wipe down but the water seemed to be getting under it, not being able to escape and hence creating mould on it.
I stipped it all down to the wood, put a white undercoat on yesterday and have just put the top coat on today. I used a gloss white as recommended by some "paint specialist" at B&Q and I must admit, it is nice and shiny and smooth so I hope it will be easy to wipe down. It's nice a bright and airy in there now - just hope the pigeons don't mind it! Next year, when I put the breeding boxes in there, I will paint them a dark colour anyway.