Hey hun
My GP referred me to the FS for IVF when my BMI was 38 and then the waiting list after that was 12 months.
Our clinic stipulated a BMI of under 30 which was fine and i dropped the pounds whilst on the waiting list.
If you can, try and go below the BMI they suggest - i gained 7lb whilst taking the pill for 5 weeks and then the down regging drugs and when i went for my baseline scan my clinic cancelled my cycle as i had gained 7lb and they said i shouldn't have done. I've never heard of anyone having this happen to them before but had i known they would do this, i'd have tried my hardest to lose even more weight. When you get your referral just check what will happen if you weight fluctuates during treatment. Good luck x