Raimey and Curl,
I cleaned up the proof stampings, with brass wire brush and solvent, and now am certain that the second digit in question is, indeed, a 6; not the 4 or 5 previously thought. So, what I have for sure is 2,67 GBP. Sorry that I couldn't see it well enough earlier, and sorry, too, that I may have mistaken your meaning Raimey, but it is now cleared up. Thanks to everyone who contributed information in an attempt to help answer my qustion, it is appreciated.