Apologies, my bad - they should have been 'ref:tiploc' (copy and paste error).  ref:tiploc has been used as per https://wiki.openstreetmap.org/wiki/UKRail_Project.  There are no tags named 'ref:GB:tiploc' or 'ref:gb:tiploc' in the current United Kingdom extract.

Subsequent change coming up to fix the mislabelled nodes.