Have you tried "Britain from Air" there are a few "incidental" views of Leicester GCR shed, which might be useful if "zoomed in" on, if you haven't seen them already.

I wasn't aware of the variations in the roof structure until today, so thanks for an interesting half hour anyway

That's interesting who is the author of the book, I have Britain's railway from the air but not Britain from the air.

Sorry! I should have been more careful it's "Britain from above" not "air", as per this website:

http://www.britainfromabove.org.uk/

Put "Leicester" in the search engine and several pics are available (after a bit of wading through),including a couple of "decent" ones (when fully magnified).The views are usually incidental to shots of the Power Station, which the GCR shed was next to.