Isn't using split advance tickets quite a risk if you get delayed? I know people are of the opinion that you are covered as the conditions of carriage allow more than one ticket to be used for a single journey but elsewhere I was told that it's your responsibility to get to the starting station of any advance ticket you have on time and in the event of any delays in getting to the starting station of each ticket you will not be covered.
This has been debated at length, but I understand that ATOC have now issued clarification to TOC's that split Adance tickets are to be regarded as one journey, and the usual conditions about being delayed during the journey are to be applied.
I stand to be corrected, although I would hope that soemone will have a link to what ATOC have actuially said!
Sorry, no, you can't travel via Lydney. (But to do that now on a Newcastle-Swansea, it would have to be a pricey 'any permitted', wouldn't it?)