This is another dish I love and I seem to struggle getting it right.

The recipe I followed was Pat Chapman's, which I found on a thread here. As I can't seem to find it again, I'll say what I did.

1. boil 0.5kg of potatoes, with about 1tsp of turmeric and a pinch of salt for about 15mins
2. Put 4 spoons of spiced oil on a frying pan, heat it up, added a heaped tablespoon of g&g and then after it stops sizzling, I threw in a mix  composed of: 2 tsp of garam masala, 1 tsp of turmeric, 1 tsp of chili. As I add the spice, it all starts sticking and making a lot of smoke, so I start adding a bit of water until there was a thick-flowing consistency. I sort of thought I may have added too much water, but I am not sure.
3. Added 2 ladles of taz base. And later another 2 and added some coarsely chopped onions, pepper and 4 tomatoes slices.

Besides the fact that I overcooked it, the potatoes were soft on the outside and a mild bit on the inside, but the end result was that the potatoes tasted too much of turmeric or garam masala (I can't discern the spice flavours very well yet) and I remember the potatoes in the BIRs in Cambridge had more of a thick sauce consistency and a bit oily.

Does anyone see anything wrong and is there a more reliable "BIR way to bombay aloo" ?

There certainly is.  Firstly pre-cook the potatoes using either CBM's method posted here or Ifindforu's method.  Then finish the dish using any of the methods posted in the bombay aloo group test, Ifindforu's method described with the pre-cook instructions or C2G's method in his vid.  It really depends on what you get locally as to what will suit you best.

CBM's method of pre-cooking potatoes:
https://curry-recipes.co.uk/curry/index.php/topic,5537.140.html

Ifindforu method of pre-coooking potatoes and producing bombay aloo
https://curry-recipes.co.uk/curry/index.php/topic,7825.msg68457.html#msg68457

Group test for bombay aloo ( for me compared to the local offerings Solarsplace and dips were great:
https://curry-recipes.co.uk/curry/index.php/topic,5537.0.html

C2G's method:
http://www.youtube.com/watch?v=WC87skY6awA

Let us know how you get on

Thanks CurryHell!

Just to confirm, though, is CBM's link an actual recipe or just a list of ingredients?

It doesn't say much with regards to timings, order of things, etc.

After some more reading, I realize what I didn't get the first time. CBM's is just a precooking method, but because it suggests a watered down tomato and then "add water until cover", it sounds more like a list of ingredients for both parboiling and cooking the bombay aloo.

today I tried  to make bombay aloo starting from a minimalistic recipe from bbc's website:

Quote4 tbsp oil
    ? tsp mustard seeds
    2 pinches of chilli powder
    ? tsp turmeric powder
    350g/12oz potatoes, boiled and quartered
    salt to taste

As I read someone in here that there is no noticeable difference between mustard seeds flavour, I chose to use yellow. I parboiled the potatoes using 1tsp of turmeric, 1 half onion, 2 garlic cloves 2 tbsp of seasoned oil. After frying it for a few mins to seal the potatoes, to add a crispiness around the edges, I was starting to feel a bit happier with the looks but when I tried the the potatoes I thought it was quite bland. So I added a little extra seasoned oil and 4 tomato halves. The looks were improving greatly, but the taste wasn't penetrating the spuds still . After 2 mins, I added  half-laddle of base sauce (I was trying to avoid the "potato curry" here) so then I let the potatoes finish to boil in the sauce and mix it often, to try and make that thicker and oily sauce. I also added a few more thinly cut onion and 3 watered down tbsp of tomato puree (w/o masala). Then I covered it and let it simmer. I can't say the potatoes were the best I had, but they tasted decently. At least, it sort of sets the mark to my next attempt.

CBM's method is far superior and will deliver the results of giving the potato plenty of flavour before you finish the dish .  If you want me to out line the method i employ using Mick's ingredient list, i'm more than happy to do so.  Just ask.  Or use Ifindforu's method which returns equally good BIR results.

Quote from: curryhell on January 10, 2013, 09:02 PM
CBM's method is far superior and will deliver the results of giving the potato plenty of flavour before you finish the dish .  If you want me to out line the method i employ using Mick's ingredient list, i'm more than happy to do so.  Just ask.  Or use Ifindforu's method which returns equally good BIR results.

I'd very much appreciate if you could share your method