Just got back from Pets at Home. Stopped by at The Blue Cross adoption centre on the way to ask some advice.
The woman there told me I can use certain other sprays, she didn't know which ones but to double check for any age restrictions. The Bob Martins spray has no age restrictions, only a weight guideline of 2 sprays per 1kg of cat. Since these cats are only 2 weeks (100g weight?) I doubt I can use it. Also seems quite a dubious product with this whole "sticky net" or w/e the system is...
She said it will be fine to use spot on @ the mother and not to worry about contact with the kittens because they won't be going to her shoulderblade area... I kinda disagree so after the kittens have fed I'm going to do the mum and keep her away for an hour or two. During that time I'll comb the kittens.
It's so frustrating though, knowing they have the frontline spray at the blue cross but can't sell or give it to me...