notice there are fewer cheaper tier Sleeper berth inc. fares available in September on non "peak" nights, are FGW expecting autumn Cornish holiday rush or have quota's been adjusted to boost revenue ?
It won't boost revenue if people don't travel and the berths don't get occupied. £49 is better than nowt.
But of course if FGW are putting up the prices then they must believe they'll be able to sell just as many fares at the higher price than at the lower.
And that of course is the gamble.