No, Belvita discontinued the 6 packer and some shops will still have stock to sell. ASDA are definitely not the only one who are selling the 5 pack
Asda's own version is about 85p, has 6 servings and is absolutely fine. Always get them now instead of belvita! https://groceries.asda.com/product/healthy-breakfast-biscuits/asda-breakfast-biscuits-honey-nut/910003121952
Oh no they're not! :)
Six packs still available elsewhere from time to time at £1. Asda seems to be the only one who's cut the pack size so far.