Hi Frank/Martin, the difference is definitley linked to business model & location. Ta's or "kebab shops" are often situated near pubs, where the clientele, footfall & rates dictate the price, quality & general time and effort spent on food to turn a proft.I saw rolls of "Mystery Meat" donner kebab rolls being delivered from a Mitchells self drive hire van with no fridge in Glasgow once. I wouldn't touch that stuff if you put a gun to my head
The Glasgow t/a's in my experience are often guilty of knocking out similar tasting curries right across their menu, often cooked by Middle Eastern's rather than Asians.
Some Pakistani restaurants are also guilty of this, but the better known places would never survive. I would
guess only that the all in method would be pretty popular in the ta's. Nobody is checking the tomato paste has caramelised correctly in Govan or Shettleston.
The quality restaurants here serve food that no recipe on here comes close to

..almost an addictive like quality to it
Interesting thing about the Ashoka(im not sure if you have been in), is that their food tastes nothing like the other restaurants I use. I find its fairly unique interms of flavour, even in their buffet joints. It's a chain within an even larger group, but there has definitely been a formula created for Ashoka restaurants.
Like Martin, if my efforts get there, then i'm happy either way-if i can cut some oil & salt along the way so much the better
Regards
ELW