Tired. .Now you're asking!
It is in the UKAIP somewhere - I haven't had to look it up since Gatwick training years ago. Gatwick has a specific outbound radar function and so it is particularly pertinent to them. I 'll have a look and then get back to you if I can find it.
I would expect an aircraft to rejoin the SID at the next convenient point, without involving harsh manoeuvres. We live in a radar environment.
Point 4