In September 2015, at age 70, I went on a trip from FNQ back to good old England [mainly a trip down the Thames] and one of the things I was eager to re-experience was eating Indian Food in the English style as compared to the 1970s when I lived there.
As I carefully planned the trip on the Web I looked at numerous Menus before leaving FNQ so I was not at all surprised that the style of cooking had changed [ie from my initial trip to UK in 1970], mainly I suspect to cater for the ever growing Take-Away market.
And yes once I got there and ate at several "Indian" [though many claiming to be "Indian-Bangladesh"] Restaurants all that was proven to be correct. FWIW back in 1970s there were more Restaurants claiming to be "Pakistani" than Indian, so there is introduced a further complication.
The big change is that the traditional SLOW cooking style where the meat/chicken is slowly cooked in the curry sauce after first being "infused" with the aromatics has been replaced with the traditional Chinese "SHORT Cooking Style", except the ingredients are Indian and not Chinese. Or one can also say the style is closer to Thai cooking methods.
The efficiency changes are obvious. Firstly only a variety of "sauces" [called Balti, Jalfrezi, Madras etc] need to be on hand [and of course may have been frozen] and the meat etc is pre-cooked [in Tandoor if desired and called Tika] and then simply popped in at the end for a quick stir fry before transfer to a Balti Dish or a plastic container for Take-Away. Secondly the wastage is far less as no decision had to be made up front on how much Chicken Vindaloo and how much Chicken Madras etc had to be slow cooked before the restaurant even opened. And the "give-away" there is that one can buy a portion of "Vindaloo [etc] Sauce" without it having started life as Chicken, Lamb or Prawn Vindaloo.
And the same goes for the Bangladeshi traditional dish of Biryani [however you wish to spell it], ie no longer is the rice cooked IN the clay pot with the meat, but simply added at the end [plus some "neutral sauce"] as in Chinese Fried Rice style. So Biryani is essentially same as any other curry plus rice except that THEY mix the two before you get to see it.
The other very obvious indications are firstly not one Menu offered beef and while one might argue the "Holy Cow" bit that was never the case before, so it is simply that beef needs slow cooking. Secondly there is no longer the all important question posed "would you like the chicken on the bone or off the bone?", because it is no longer COOKED on the bone in the traditional way.
So was it better or worse?
I'll answer that indirectly by explaining that while I have the long term habit of actually COOKING curries about 4 times a week [for over 40 years], I also cook the occasional "Chinese Stir Fry", though without much knowledge/expertise. The method is to stir fry big chunks of onion and capsican in a wok in hot oil, add a packet of paste (eg Mongolian Lamb) and throw in some prawns or chicken etc and give another short stir fry before serving hot on a bed of rice or noodles.
I always enjoy those meals (ie as well as curries) but they do not have the flavour or variety of what one can experience in Oz at "the local Chinese" to be found in the High St of any Oz suburb or town.
And here we come to the point of the matter, ie "Australian Chinese" has developed a unique Australian version of Chinese cooking (with invented words such as "chop-suey" etc) that over the period since WWII has spread in that same consistent style over the whole of Oz as "an institution" and a successful one at that.
All that was BEFORE McDonalds or Pizza Hut etc. When these finally came along the consistency of the marketing was controlled by Big Brother. But the amazing consistency of the "Oz-Chinese" was simply from what Charles Darwin called Natural Selection, ie the selections that were the most yummie like Sweet & Sour Pork were the ones that got ordered all over Oz and therefore the INDEPENDENT thousands of Oz-Chinese Restaurants all fell into line to promote that product.
The result was the much satirized "extensive" menu at your local "Chow Restaurant" where you say "I'll have a 53 and my wife will have a 69".
Back to UK-Indian, for better or for worse, the conglomerate of "Indian Restaurants" decided NOT to use the numbering system BUT everything else about the extensive UK-Indian Menu structure is the same as for the Oz-Chinese.
Terms such as Balti [and please Google re Phall as it is amusing] were invented, the same as for Chop-Suey and Chow Mein in Oz-Chinese marketing, so instead of a heading of "Chop-Suey" etc you will see "Jalfrezi" etc with the same choices of "chicken/pork" etc set out below.
OK, all that is smart marketing [ie in UK as well as in Oz]