does anyone know how long it takes to get approval for this group? Sent a request last week and not heard anything yet.

Would be interested in this - could you send me the link please?

I can't remember it taking me very long -probably all hinges on how busy the admins are. There are currently 3726 members whereas 228 are new it says so probably a fair few apply.
https://www.facebook.com/groups/437285963014314/

Thanks have sent request :)

Didn't take long, may be people on holiday plus high demand