All in all a successful quick dinner in 30 minutes.

I was in need of a fast meal for 5 and had 3 large chicken breasts requiring use, so I gave this a try. I followed the linked Butter Chicken recipe quantities as given with the addition of a big spoonful of Patak's commercial Butter Chicken Paste and a half cup of water as I had nearly 1 kg of breast fillet (almost double). It did produce a nice easy curry and the preparation was nearly nothing so there is benefit there. Nobody complained about eating it. I guess it is an American influenced recipe as it uses Cayenne Pepper which I substituted for more Indian Kashmiri Chilli Powder.
My only issues were the texture of the chicken and looseness of the sauce. I don't usually cook chicken under pressure and the reason was clear again. The chicken chunks began to break down in texture and some pieces would literally shred when stirring in the last stages. Easily remedied next time by doing the sauce for a few minutes on saute before adding the chicken and then do less time under pressure. Chicken thigh fillet would probably be less prone to breaking up.
The sauce was a bit thin for my liking so I added a TBSP of corn flour / cold water slurry to thicken it up a little right at the end. This may have been my fault as upon reading the whole blurb, I did notice that there are suggestions in avoiding loose sauce and also the fact that only half the sauce is meant to be kept in the finished dish. I did neither of these. I just did a one pot cook with everything in on curry setting for 15 minutes with slow release for 10. Possibly over-cooked it but it worked OK.
The method in itself shows a lot of potential and the dish was enjoyable served with boiled Golden Basmati rice, steamed veggies and a few Parathas.
A lot of potential here Robbo.
Edit: I shouldn't have added the half cup of water. Pressure cooking in a sealed vessel requires minimal liquid. Note for next time.