Went to buy a bit of WD40 and it scanned at the till at 1p!
Unfortunately I threw away that receipt because I wasn't thinking about posting the deal until today (I bought yesterday Monday 17th Oct). The guy on the till couldn't explain why it was that price so I assume it is national. I can provide the SKU later today when I get home. If you pass a Wilko, try picking one up and see how it scans! I didn't check the 250ml.