It's incredibly hard to find in white these days, and when you do it often goes for silly money. There are alternatives, I use Cat Eye 'Shiny Tape' which often comes up on Ebay in a white/pearl colour. I've not compared the two side-by-side but from what I can tell from photos it's close enough.
1989 Raleigh 531C Race
1990 Raleigh Dynatech Castorama replica
1991 Raleigh Dynatech Lo Pro TT
2012 Raleigh Airlite Campagnolo Centaur 10 speed
2013 CYFAC Proxidium Campag Athena 11 Speed
2013 Team Europcar Colnago C59 KoM edition