I always wonder what the train companies expect their customers to actually do in this situation. It appears that the choice is between:
1. Wait to book your outward Advance tickets until your return ones also go on sale. This means you will have the surety of being able to both go and come back at suitable times but accept the very large risk that your outward tickets will increase in price between now and when you are first able to make a return booking. This means you have not got the cheapest deal that you could have.
2. Book your outward tickets now and then book return tickets separately once they become available. This means you secure the best price for your outward tickets now (or so they would say, at least) but with the risk introduced that the timings and prices may be unsuitable for your return journey and you are then stranded, unable to get a refund on the tickets you've booked, but unable to book a train homeward, so you can't use them, either.
I think most people would be much more circumspect about the negative consequences from 2 than 1, but conversely I think that the chances of the disadvantages associated with 1 actually happening are much greater than 2. Such is the nature of humanity. If I were in this situation, I would be inclined to look to travel by some mode other than rail for all or part of the journey. Of course, that's not always practical. You might find that, for example, you can book Virgin Trains for your outward journey and a National Express coach for your return journey at suitable prices, and both at the same time. It can also be possible to book with other train companies, or modify your travel dates or times slightly. In many cases though there will be no alternatives that fit in with your trip, which I do appreciate. This problem is exacerbated hugely if other services need to be booked at the same time. For example, long-distance rail travel is often booked at the same time as overnight accommodation, flights, sailings, car hire or tickets for special events. All of these can easily be time critical and non-refundable. If you are looking to book flights and hotels these are almost certainly going to be available, even four months out, and very likely to increase in price if you don't grab them. If your long-distance rail travel to the airport won't be open for booking for weeks... what do you do? Most people's answer is probably not go to by train. But I digress.
As the problem with return tickets has effectively been created by the TOCs and acts to place them at a competitive disadvantage against other modes, I wonder what their official line on the matter would actually be? The sums of money involved are often very significant - on many popular routes where tickets can sell out very quickly at certain times of year, the difference between getting an Advance right after it goes on sale and getting one two or three weeks later can easily be a factor of two or even three. On a long journey like this, that could amount to a huge sum of money. Maybe you should write to VT and ask them what their official word is? After all, it's a problem they have created, not you, and it's not at all difficult for them to solve. They could, if they wished, easily allow you to book and pay for an outward journey and hold it 'in escrow' for you, to be alerted automatically by text or email when booking for your return date is opened. At that point you would have the choice to add a return ticket to your booking based on the prices and times that have been put on sale - or to get a full refund on your otherwise non-refundable Advance ticket if none of the return times or prices meet your requirements. It would probably be of significant net advantage to the train companies to offer a service like that, because most people who look currently will either be put off by the artificial disadvantages created in points 1 and 2 above, or more likely be shown the very high Off Peak or Anytime ticket price only, and abandon the idea of travelling by rail without investigating any further (even if a really good value ticket were actually available for their outward journey!).
If you set out to the customer relations at Virgin Trains the dilemma that their retail system faces you with, they might agree to allow you to buy the outward tickets now, on the special terms that if you can't secure return tickets with them that are to your liking between now and the day before your journey, they will allow you to have a refund on the outward tickets. Of course, they might choose not to offer you that. I would be fascinated to hear what they think, though.
