I have never seen a LFS that carried any kind of ammonia. They will tell you that ammonia kills fish, which it does, and that you don't want it in your tank so they don't carry it. They miss the point that to develop the bacteria to remove ammonia, they must be given the ammonia to grow. That concept seems to elude them completely and they tell you to cycle with hardy fish, a source of organic ammonia that they have in stock.
If you found your ammonia at Boots or Home base, you must be in the UK. In the US you would have found the right stuff in the cleaning aisle of an Ace/True Value Hardware store.
Yeah although I think the people who work there are just uneducated about the whole cycling thing or their corporate doesn't know the right things to sell!
I'm in US, so I may just end up going to Wally-World.
And here is a n00b question, but what does LFS stand for? Live Fish Store?