Hi JerryM - thanks for the reply - I have tried many ways of spicing the green base mix when boiling - After I asked my wife to get the base going for me as I was stuck late at work, when I came home i found that she had applied a generous over-measure to whole green cardamoms (and cloves) - instead of approx 5 - 10 as I had suggested - I counted 30 or so of the blighters in there!
Having said that, the finished curry was not as bad as I thought - just goes to show that cardamom is a necessary generic flavour..suffice to say I then tried just adding a desert spoon or two of garam masala along with a couple of star anise and green cardamoms which works fine as well - just as an emergency if I need someone else at home to get things going in a hurry
Haven't tried a spice ball - may look at that - I have just purchased a villaware 1000w 2l blender so I am confident that any spices that I may miss left whole in the green mix will get completely pulverised when I blend it up
Thanks for the links...

Hi beachbum, yep I managed to get a cast aluminium bodied gas BBQ with a high lid and temp guage ( not that I believe it is that accurate ) off ebay from a local guy for ?18 ...with both burners only on low to medium, the temp gets to around 300 degrees c...I have made tandoori Chicken and chik tikka with success - at least its nearer to a tandoor than my oven!
May look at using one of my spare porcelain floor tiles in there as a naan platform - one of the first things I did with it was smoke a brisket by raising the meat up on a stainless Steel basket on the right hand side ond only run the left hand side on low...My next attempt at chicken tikka will be similar but running the burners on high and having the skewered meat standing upright - I suppose I could drill a hole in the top to drop skewers through in the style of a real tandoor...will think about that if I can have some kind of hatch to close it up if need be.... 

Hi - I have always been a foodie and the allure of the BIR curry has had me trying all sorts for the last 35 years - once I read 'The Curry Secret' quite a few years ago - my curries came on in leaps and bounds - now having found this site, this last weekend I was able to make three different curries and Tika  Plus Tandoori on my gas BBQ - and I feel like a new breath of life has come into my cooking. Thank you so much for all of the peoples efforts to keep this running and all the contributions!
So far the biggest things I have learnt since (Friday!) were, making and use of mixed powder, using other veg in my base sauce mix, how to make a BIR style Biryani and the copious use of Coconut powder and evaporated milk to make an old skool Korma that my kids loved....next is shammi kebab and keema naan - my favourite restaurant that used to be here in Portsmouth always seemed to use the same meat in keema naans as shammi kebab - and again all my kids love keema naanas so nailing that one will make me even more popular

They also seemed to have a generic flavour of aniseed, albeit subtle, in most of their dishes and I have not decided yet if it was due to fennel seeds in the mix, star anise, or fresh fennel in the curry base...but next base for the weekend is having fennel root in it....

Thanks again