What's your view? That there's pressure to end 'spare at home' because management just wants to inconvenience train crews?
See, it's churlish comments like that which get people annoyed. This is a discussion, not a battle.
My view, as it happens, is that it doesn't matter whether the driver is spare at home or at the depot because it make no practical difference. A driver spare at home needs to phone-in in advance of their booking-on time to speak to the traincrew supervisor (TCS) to find out if they're needed immediately so that they can attend in time. If needs be, they can still get to work by their booking-on time. The driver remains contactable throughout the shift and can be called in when required (subject to travel time).
The cost implications are also no different. If a driver is spare it is because they are not immediately needed at the time the daily alteration sheets are published nor at the time they book-on. If they are not required on the day then they will sit around drinking tea and staring out of the window until they are released by the TCS. In this instance it doesn't matter whether they're at home or in the depot.
If there is a need for short-notice cover, this will be dealt with by the standby driver. This is different from spare because it is a rostered turn and requires the driver to attend. As was explained earlier, if there is a need to replace that standby driver then a spare can be called in.
That's the procedure. In practice, various factors currently at play mean that no-one is spare. I haven't been spare for so long that I have no idea whether or not we're even still doing spare at home. The spare cover built into the roster is being fully utilised at the daily mark-up stage and still isn't covering all the gaps (even with a reduced service), hence my comment about the consequence of reducing spare coverage.
Where there is still spare cover on the day, the TCS is usually well aware of what issues he/she will have to deal with in advance such that the travelling time of a spare to attend from home is not an issue. It is commonly the case that when you speak to the TCS you are told what you are required to do several hours in advance. While this does not mean that the need for a short-notice cover driver does not exist, it is usually limited to major disruption events which would allow the TCS to redeploy the existing on-duty drivers as necessary due to service cancellations.
It won't, I imagine, be proven on a public forum to your satisfaction. Indeed proofs of anything are nearly impossible in the universe, unless you're really good at physics.
However, most of us consider the available evidence and come to a view based on what's most likely going on.
Actually I'm not expecting court-levels of proof. I simply believe that any comment that masquerades as a fact should be capable of substantiation and that I should not simply believe something because you or anyone else says so unless I know that they are a trusted and knowledgeable source. Therefore, statements like those that suggest that "spare at home" is causing service disruption should be capable of being backed-up or should otherwise be clearly phrased to show that this is the poster's opinion.