Final word to 'just allan' who summed up how I felt it would be as a day out - very Indiana Jones!
"What a treat! Today I popped out at lunchtime to visit the National Museum of Scotland Collection Centre. The lovely Witch Creations had organised the visit for us and it was a real Indiana Jones treat to be allowed into the inner sanctum... etc... etc. Anyway, lovely people and machines.
This is a Rudge-Whitworth, which is one of many historic bikes curiously presented in this warehouse. I say curiously because this isn't intended as a display, but as a storage facility. Yet it's all very accessible and well lit. A really lovely way to invest public money. This is about 100 years old by the way, it looks like 1920. (It was labelled but I neglected to take a photo of the information card)."