Assuming you have all the above qualifications under FAA, the following is required for conversion
1) A Class One Medical. Only done at Gatwick
2) Sit and pass all 14 ground school exams.
3) Pass CPL training as required, then pass a 170a and subsequent CPL skill test.
4) Pass a multi engine skills test
5) A minimum of 15 hours of IR training, then the 170a and pass the IR skills test.
6) Take shiny pieces of paper to the CAA, pay a wad of money and then wait 4 weeks for your licence.
7) Enrol on an MCC course.
This is what is required as a minimum, I would stongly suggest you have a contingency as only sky-gods convert in minimum time.