Welcome Graeme. Greetings from the East Coast.

Yes Indian restaurants are becoming far more popular here than even 10 years ago. Going back 20 or 30 years there were very few indeed, perhaps only two or three in each capital city. Then with increasing Asian migration and especially Indian and Pakistani migrants from the UK itself, Indian is becoming a growth industry.
Now I had the pleasure of visiting a Sikh restaurant in 1983 which was only just a few years after I'd migrated here myself. It was on the NSW North Coast at a place called Woolgoolga which is at the centre of a huge banana growing region. The industry was set up by Sikhs decades ago and there are hundreds of them - and they opened a BIR style restaurant for tourists, Woolgoolga being right on the National Highway and is a popular surfing beach.
My recollection was that the food was spot on BIR, Mrs and I had Chicken Biryani with the veg side curry and Lamb Dopiaza IIRC. I was right back in the UK

Nowadays although the current offerings at our local restaurants are ok, they are nothing to rave over and I wonder when and why the "rot" set in. You obviously noticed it when you arrived recently.
My curry cooking has literally been on the back burner for a couple of months as we are moving interstate, but with the aid of this forum and the various E books you can get I aim to get my cooking started again and give the BIR a real nudge this time.
Note: unfortunately the restaurant at Woolgoolga has closed down. Following a massive cyclone that destroyed the QLD banana crop, bananas went up to $12 a kilo last year and the Woolgoolga / Coffs harbour (NSW) farmers made a freaking fortune - why slave over the pots when you can sit back and watch the yellow gold grow in the fields. haha.