Nice idea... unfortunately Strand also used to be a cigarette brand so this doesn't have a unique solution.

Likewise Marlborough... but it can be very difficult to get the right number of crossovers to create a decent challenge AND have a unique solution. And we all have the occasional typo. I enjoyed it.

Ah, you got me on the tube station group. The only thing I'd say is it may not be a great idea to put what the clues are red herrings for as it gives away that group if you look at the connection before you've guessed the others (that is, if you are guessing like me - if you know the answer, not so much of a problem).

Good one - nice red herrings