Hi Muz. If you have an externally venting Blow Off Valve, you can most certainly blame that on your stalling problem. A lot of people opt for changing over to a nice loud BOV and find that the car begins to run rich and stall frequently. They then end up putting the factory BOV back on.
To solve the problem you can purchase idle stabilisers and the like, but if I were you I'd purchase an internally venting BOV like the factory or swapping someone with a factory one.