100% the old 'white t&e' was not LSOH. I've seen discussions elsewhere and noone seems to know why two variants were produced, but distribution does appear to be regional. Here in the Midlands you could get grey at one shop, walk into another and it was white.
The only trend I noticed was the white stuff seemed more prevalent in DIY type shops. I'mm looking at a length now - it's just normal supple PVC, but white. Then post 2004 it became LSOH.
On the contrary at our site, there's some grey "old colour" t&e marked as LSOH