I think he wants them ready fried, like me, why go to the bother of frying onions if you can get onions that someone else has already chopped and fried, it saves on the washing up. In answer to your new question about Asian supermarkets fartalot (what a cracking name!), what you need is a corner shop, a Londis, something like that, surely there must be a few of those around you ?
I've bought them in Sainsbury's; admittedly this was about a 12months back. Can't say if they are now on sale in my local supermarket, which has been 'up-dated' and in the process has, in my opinion, taken a backward step. I'm in correspondence with Sainsbury's on the question of their store now having gone 'down-market'. ... ..Ron