Follow up:
Unfortunately; time wasn't on my side,  so I ended up in a large pan.
Fortunately though; my Base gravy recipie was quite rich and thick (saves freezer space) and I had used a bit of mixed powder in the Base (can't remember which Base I used)
My precooked chicken sauce also contributed to the curry and since it is only me who is eating it i was happy to throw it in once I had fished out the big spices...  Luckily there was a lot of (now spiced)  oil on top of my precooked chicken so I skimmed that off to start the big curry off,  used about 2 tbsp. If gg paste and made my curry as usual,  added tomato and cooked for a bit then mixed powder until the consistency was right. Then Base gravy,  boil, precooked chicken in for a few mins served in boxes ready for work .
All in all it seemed ok. Could have been a lot better,  as I didn't manage to get the more cooked bits around the edge of the pan...
But yea: ppl still take some convincing that it's not takeaway  :/

Thanks all for suggestions,  with more time I'll be doing individual portions and combining after

I have about 1kg chicken and 1l of gravy to use up.  So maybe 5 portions,  I'll save whatever sauce is left over

Should it be done the usual way in individual portions,  or in a largeish stock pot?
I have my precooked chicken and my base gravy waiting to be combined, but I only want one curry (but several portions)

Thanks for the Reply, I have read a rather lengthy thread on the book, most of the 36 pages, but I'm going to give it a good try. I'm not a Scot, but coincidentally my first curries happen to be whilst I was working in Scotland. I'm from Lancashire.
There is a lot of information on this forum that I will have to wade through, hopefully I'll get closer to the result we are all striving to achieve.

I'm not sure if a story is required but here is mine:

When I was younger, I would try my dad's takeaway curry on a piece of peshwari naan, and would always feel Ill after, this lead to me to a 10 year boycott on chicken (me blaming that for the illness) tried chicken about 4 years ago or so and felt fine, had a diam bar and was Ill. Turns out it was almonds I was allergic to... so about 3 years ago I had my very own curry at a restaurant. Although not the best experience as it was recommended I had a Korma... but my almond free experiences have been very good since! Scene as I enjoy not spending a lot of money on things, I figured: I'll make my own curries... so my quest continues. I requested the under cover curry book for Xmas and have since made a good 20l of gravy. So I figured I'd post some of my experiences with it (in another area of the forum perhaps). As can be deduced from my introduction, I am a beginner. But I will contribute as much as I feel will make a difference.