Just been in to Sainsburys and wanted to get some more Hedrin to have 'in reserve' They had 100ml bottles of the once use gel stuff for £2.50!!
I think maybe it should just have been for the gel that you treat twice with but I checked at customer service and the once stuff came up at £2.50 so I bought three bottles. Too cheap not to. Hope this isn't just in the York Sainsburys and will help someone 