I needto travel Durrington to Taunton return, out via Salisbury, return via London. I know I can buy a super off peak return via Salisbury and get a change of route excess for the return to an any permitted ticket via London. I've done this before ,no problem, but always direct in London via Paddington and Victoria. My question is, can I use this to travel to Farringdon and change there ( I need to break my journey at Farringdon)? And if I can, will the gateline at Farringdon allow me through both out and in, even if it is clearly valid, as I wonder if they'll know about change of route excesses?