Those packs do look very good, ROB75. Will keep an eye out for them if I'm in Costco anytime soon. Might get one for the other half as she doesn't have a hydration pack just now.
After I reserved to collect the Camelbak on the Halfords website, I didn't get a confirmation email. Thought that was a bit strange but it definitely went through as the page popped up to tell me it would be reserved to collect until tomorrow evening. Didn't print it out ( I should have I know ).
Anyway, drove through to my local store and they had no record of it on their system and none in stock at all. To be fair the guy was willing to discount a different pack down to the same price but I wanted a Slipstream. So gave up and came home. Reserved another one online but it is at a store about 11 miles further away. This time I got a confirmation email and printed it out.