I shall re-visit this base to experiment with -  perhaps add garlic and reduce the cardamom . Another project for the weekend . 

Looks great - well done ! 

Welcome to the forum - enjoy the labours of your curry companions .

I think that four days is pushing the limit - this will not improve the flavour  but rather tend to break down the fibre of the meat so as to render it a congealed mass with no texture or body  - might as well be eating a pudding .  Any marinade that contains acid, alcohol or salt should not be used for very long, because it will chemically "cook" or denature the food in it. Marinate food in these marinades for less than 4 hours. Marinades that contain citrus juices, especially lemon or lime juice, should be used for only two hours or less. Marinades that contain no salt, acid or alcohol can be marinated overnight or, in some cases, longer.
Although marinades thwart bacterial growth and help extend food's life, remember that the food in them is still raw and must be treated as such.

Just an observation .... there are so many CTM recipes out there - which one is the BIR authentic . I have eaten CTM at numerous restaurants both in the UK & North America -  no two restaurants are the same . So guys , the question is  - if CTM is the foremost dish in the UK , what is the best recipe ? Which taste reigns supreme ? From what I can gather . there are over fifty variations of the this Uk developed dish -  could we possibly short-list the former ?

CC

Looks fab ! 

Hi baby spice .

There are a number of good curry bases on this site and all are worthy of a try . Follow this link - https://curry-recipes.co.uk/curry/index.php?topic=422.0
The taste of the base can vary somewhat so it tends to be a matter of personal preference . I would suggest you try Darth's , Pete's' , Mark J's' , Ifindforus'  or Bruce Edward's bases to begin with . As for recipes , follow this link - https://curry-recipes.co.uk/curry/index.php?topic=415.0

Enjoy 

CC

Karahi - vindaloo - and rogan gosh  are three of the dishes where I do not incorporate a base sauce... I prefer to make them from scratch using the more traditional recipes . This is  a personal preference based on the taste outcome....others may differ - but I much prefer the taste that is created . This is one of the unique benefits of this site....we are all free to experiment and incorporate either traditional or BIR recipes and find a taste that pacifies our palate . The true defintion of BIR is rather broad ( to say the least ) . The taste can vary from region to region...it is just a question of - what do you like !

Remember that you can always tone the recipe down a tad and then kick it up a notch for those that wish to " enlighten the taste buds " . 

CC

I think that this step is basically personal preference - based on previous experiences with the recipe .When I make this base I reserve 50% of the oil in order to preserve the taste . Experiment a little and see what you prefer . 

CC