Deano777,
Good news -
LASORS Section E is online!
do you need a certain number of hrs before commencing the night rating
No - you can do the night qualification as part of your initial 45 hours training.
as with the 70 hrs needed PIC to start the IMC
You don't need 70 hours PIC to start the IMC training! All you need is 25 hours after licence issue, which can include the 15 hours (or however long it takes you) for the IMC course itself. This is also in Section E.