I'm curious about this assertion. So I checked a few random items from this weeks grocery shopping (the pound is at around £1=HK$12):
Chopped tomatoes:
Wellcome - $11.50 for 500g (Parmalat)
Sainsbury - £0.99 for 400g (Napolina
Tin of tuna in brine:
Wellcome - $11.90 for 185g
Sainsbury - £1.09 for 200g
Port Salut cheese
Wellcome = $47 for 150g
Sainsbury - £1.77 for 185g
HP Sauce
Wellcome = $19.90
Sainsbury = £0.84
Jacob's Creek Shiraz (I accept there's a duty difference also)
Wellcome = $83
Sainsbury = £6.86
Own label unsalted butter 250g
Wellcome = $19.90
Sainsbury = £0.98
Skimmed milk
Wellcome = $18.50 (946ml)
Sainsbury = £0.86 (1.13l)
Toilet Paper Andrex
Wellcome = $36.90 (10 rolls)
Sainsbury = £4.00 (9 rolls)
It seems to me that for unrefrigerated items Wellcome is already cheaper than Sainsbury's (with the exception of HP Sauce, which I guess is a bit of a niche product here)
The refrigerated items seem to be about one and a half to twice the price of the UK.
So if you can get refrigerated transport to my door for a weekly order of perhaps $200 and can undercut the Wellcome prices then I might be interested. But even then it requires me to be in when you deliver so I'd need a pretty precise delivery time.
Otherwise, thanks, but no thanks.