I agree with you about doing Standard class on London-Edinburgh. There’s a seat shortage at busy times.
In this month’s ‘Platform’ (where i compared Little Red with East Coast) I suggested that some rail passengers might defect to Little Red seeing as it was a fresh new brand and that its fares might undercut the train (depending on tariff type, how far ahead you book and so on).
You’ve obviously secured a good deal with Little Red and BA.
Perhaps you could let us know how busy the Little Red flight was after you get back.