Immediately after starting this thread I sat and searched for balti information while i had a cup of coffee. I sat for about a half hour and you probably won't be surprised.
First I checked around a bit to see if I could go and buy one. There are 3 well regarded Indian restaurants around me, one of which was award winning for consecutive years. I've dined at all 3 over a period of 30 years and enjoyed it every time. A Balti dish is not on their menus. So I searched for Balti in Sydney and the top link was to a restaurant called The Colonial something which claims to serve British curry. A report on Trip Advisor claimed the Balti was the best this side of Birmingham. Promising. Checked the menu. No Balti. Come to think of it, I can't recall seeing a balti on a menu out here.
I then started looking for balti recipes. Every man and his dog (plus women as well) has a recipe for Balti Chicken. Of course they are all "authentic" and they almost invariably have a little story about the origins of balti and then present the recipe containing balti paste. Within a very short time I'd read about 20 ingredient lists. I even watched a video of a BIR Chef cooking Balti Chicken w/ Pataks paste. Pataks even have there own videos on how to make authentic balti like a chef. Some recipes have sugar added. Some also have lemon juice and that reminded me of the Mr Huda ingredients.
So then I looked at the pastes. They have sweetening (mango chutney) and souring agents. Tamarind or lemon juice and there are mentions of food acid and citric acid. (Not uncommon as it's for preserving) None of these sweetening and souring agents are in the 3 balti restaurant videos. I think Jamie Oliver adds citric acid in his recipe. Why?
On to recipes for balti pastes. There aren't many. I again found the one that I have been using for over 10 years. I found one that is a possible contender using less spices and then there are a few that supposedly show how to make balti sauce or balti gravy but these are individual dish preparations and not a preserved paste. When you look at the spices used in the 3 Birmingham baltis, it is nothing special so a good usable balti paste (preserved) should be a relatively easy project to nut out using basic principles.
I thoroughly enjoy the balti paste I make and use. It adds wonderful flavour and I've had jars keep in the fridge for several years without issue. I have no problem adding a good dollop to Mick's 100% clone base gravy when cooking balti chicken. I haven't recently tried Pataks balti but I do use their commercial butter chicken paste, which i quite like, and use frequently. Many years ago I used to use the Pataks balti stri fry sauce (and other flavours) that came ready to cook in a tin can. I don't see them any more, not that I'd use them now.
The other paste I regularly use now is Rik's (loveitspicy) Madras paste. Using a tsp of this with about 2 tsp of home made balti paste in a double serve of mdb's balti chicken makes a great curry, and I'll call it a balti every day. It's probably closer to a real one than most online.
I noticed last night that my container of Balti Garam Masala is empty so today I will research and compare these spice blends. I'll wager there is a wide variety all supposedly the same thing.
Wait until you see the balti I prepared last night.

Absolutely delicious and the ingredient list will surprise you.