To be honest, I'd drive the whole way from darkest England
Ah, well, that's because you are not in possession of all the facts.
The little dears are in orchestra school in Aldeburgh, with a concert ending at 1600L. They are supposed to be in a coach leaving from London for said religious summer camp at 0930L same morning.
Camp are not prepared to accept them any later than the evening meal (ca 1900L), and they are a bit cross about the trouble they are being put to even allowing that (religious types, don'y'a know). You know (better than most of us) that religious people think that they have first call on people's time.
So
(1) Aldeburgh to LLanuwcchllyn is no way 4 hours (TheAA.Com suggest 5.35, and that's without traffic)
(2) we haven't got four hours anyway
(3) I have then got to get back from LLanuwcchllyn for work next morning, and
(4) Driving London - Aldeburgh- LLanuwcchllyn - London is not my dream Sunday.
Apart from that great idea!
W