night fi rating
If you have a night rating and 10 hours night then you can do the night instructors rating as part of the FI course, eg within the 30 hours flying, it involves 1 hour night training and a minimum of 3 hours ground school. In Scotland it is a useful rating to have as it gets well dark and I happen to know the flying school you mention would normally include it providing you are competent on the day flying!
The imc instructors rating, although 5 hours and 35 ground normally takes more than the 5 stated, to get to test standard, also you need 50 hours IFR and an imc rating with no restriction.
Its my humble opinion that there will be a drastic shortage of imc rated instructors soon as an unrestricted FI can do everything a QFI can bar teach IF, also no imc requirement for CPL issue any more. Hope this is of interest!