I have uploaded the script to another site - mediafire - I have never used this site before but it looks like you should be able to download the script from there easily enough.

What difference would it make - isn't Ordnance Survey already a private company focussed on making profits? Still, I wonder how much it would cost to buy them and free the data...?

Yeah, it's grayed out on that map so it's "proposed" only, but the signs are up and the route really exists :-) Apparently it's only been signposted for a few months, and it's a bit patchy at points - I had to go back and look to make sure I'd followed the right route several times, and there's a distance of about 5km that I mapped without signs where you join the B1348- the sign directs you left onto the B1348, but then it seems you cycle for a long time without any confirmation. Maybe I'm just used to seeing route stickers more often, or maybe the sign is wrong and you're meant to be on the John Muir Way here... speaking of which, they're looking for volunteer rangers to maintain this section of the route http://www.everydaycycling.com/edc/news/news2008/20080630_round_the_forth.aspx

Did you tag some of the Pentlands routes as rcn? rcn is for official signposted Sustrans regional routes - see http://www.gravitystorm.co.uk/shine/cycle-info/ - they're numbered, not alphabetic.