Thank you for the advice, even if it doesn't provide the answers I'd like to hear. Am I right in thinking that a TfW/LNR service will soon be running between Euston and Chester? Or is this just wishful thinking? The Avanti service for the same route is very expensive and very unreliable but I suppose that goes without saying.
There's no chance of a through service competing with Avanti - the line from Crewe to Chester is unelectrified and LNR's paths on the Fast Lines only work with their 110mph 350s. If anything, the only extension I could feasibly see happening would be to Liverpool, or possibly Manchester Airport. But both of those would be fanciful in the current cost-constrained environment.
Another option, again slower than just your single change at Crewe, would be to go via Runcorn. You'd use the cheap TfW only £6.20 Chester-Runcorn CDR and then an LNR only fare from there to London, £38 for the Super Off-Peak Return. So a total of £44.20. Unfortunately the connections at Runcorn aren't great and TfW is only running their Chester-Liverpool service every two hours at the moment.
A second option would be to buy a Merseyrail Day Saver for £5.60 to get to Liverpool. And then again it's £38 for the LNR only Super Off-Peak Return to London, so marginally cheaper at £43.60. (You could alternatively use a Saveaway which would also give you bus and ferry validity for an extra 5p.)
And third option would be to buy a Chester-Shrewsbury Off-Peak Day Return (£12) and then a Shrewsbury-London TfW & LNR only Super Off-Peak Return (£28.50). This would make for a total of £40.50 but with the various time restrictions, it's virtually impossible to make day trip using these tickets.