I was prompted to return this back to the BBC following the recent ta'do about religious costume, also from the Not The Nine O'Clock News team :
http://2.bp.blogspot.com/_tz_6DoOC8N0/SY1s1DqWp8I/AAAAAAAAAY8/eHDIFmni1q4/s1600-h/Not_Ayatollah_g.png
I could do with one of those in PVC at the moment (will it ever stop raining?).
Going by this the correct certificate would have been yellow (not green as I remembered it) :
http://www.youtube.com/watch?v=Cx1_e2VnvOg
Those of you intrigued by the sample certificate it dates from 1979 (not 1980 as often listed) so a perfect template for Star Wars and ESB and bits of this classic can be seen here:
http://www.youtube.com/watch?v=GxZ1xn2ml10
I can't make out what the pattern in the margin is (could it be the BBFC address?), different aspect ratios, I assume, would have just extended the coloured side.
I will have a go at replicating it when I find the time but if anyone can give more concrete details of the side margin I would be very grateful.