Having lived in St Andrews for about 5 years and still visting there every weekend, my local BIR has come to be The Balaka. The Balaka is a fairly upmarket BIR and won the Pat Chapman's best Indian restaurant in Britain 2001.
I go there regularly with my gf and we spend quite a lot of money. After reading their website
www.balaka.com/ it talks of a herb garden and says feel free to ask for some fresh herbs to take home when visiting the restaurant.
So, I did the whole "so I hear you have a herb garden outside" thing, and one of my favourite staff members there, a middle aged Indian man, actually took me outside to this large allotment where they grow their fresh herbs and gave me some Coriander while we had a great conversation about growing herbs etc.
With friendly customer service like this, I wonder if I would be in with a chance at watching my curry being prepared, or even for them to write down their base sauce recipe, because the quality of there food is top notch.
The thing is, I wouldn't want to come across as out of line in my request as I really like these people and they give me discounts, free popodums etc, something I really don't want to put on the line :

How should I approach the issue of getting The Balaka to share some knowledge with me?