Just goes to show that 5-car units aren't really a good idea for Great Western Intercity services. If they only have 5x 5-car units (4 diagrams) and still can't avoid having to diagram them onto two trips for which they aren't sufficient there are clearly not enough quiet services for 5-car units to be useful.
I suppose one thing you could do is only bring them out at quiet times and have them sat idle the rest of the day while longer trains do the work. The overhead of maintaining two fleets would probably exceed the savings from running shorter trains when the long ones aren't needed though.
There you go again, you don't know the situation but that's not going to stop you demonstrating your blind prejudice about five-car trains, is it? A five-car IEP will have more seats anyway.
There are plenty of services that the 180s are useful for, as I keep trying to tell you, but yet again you just don't seem to take in information that people provide.
FGW is sending HST sets to Kilmarnock for heavy overhaul to get them through another few years of operation and in order to do so has withdrawn the diagram that saw an HST work the 06.40 Bristol-London service, then spend the day at Old Oak Common before going out on the 15.51.
FGW know full well a 180 is too small for the 15.51 but there's nothing else available now. And the 17.18 empties out nicely at Maidenhead - like pretty much everything else calling there at that time of the day, such is the demand at that station nowadays.
The 1718 isn't an intercity service, it's semi-fast at best. The 1552 doesn't have to be covered by a 180 because there is nothing else the 180 could do but because there is no longer an HST to work it. The 180 used to work a couple more Oxford services instead. But it is better that a 180 replaces the HST on the 1552 than a Turbo.
Not really, both types are grossly over-crowded on that service, and were years ago, which is why it needs an HST...
You seem to be confused about which Oxford semi-fast was an HST until last year - it wasn't the 17.18, which was always a three-car Turbo - I used to see it arrive in Oxford much of the time. The HST was, I believe, on the 17.35, which is now a pair of Turbos.