My thanks to Andy D. who has taken the trouble to write to me (not being a whiz at computers) alerting me to two different rouletting patterns on the gold medal stamp base sheets.
The bases sheets are printed, die-cut and rouletted by Walsall Security Printers so this is down to them. On the sheets that I've examined I've only found this on the side rouletting adjacent to the fourth miniature sheet, which is good news for people who have only bought that MS:
As you shown in the image, there are 4 extra long roulettes (or uninterrupted) on the left-hand sheet. This is not restricted to GMW07 or to one printer location, and could be found on any sheet. As the sheets are printed two-up on the web, this difference probably occurs on one side only.
I've not had a chance to examine the horizontal rouletting between the MSs and will be pleased to pass on any information that you have, preferably with images. (And see the comments below for other people's findings.)