In my time, so not sure how much, if anything has changed, the majority of crews who worked Windsor side services were based at depots which had a far wider variety of work (main line wise) and so will retain Desiro knowledge going forward I would guess. If my faded memory is correct, may be only one depot that currently have Desiro knowledge might stand to lose same in laymans terms. But that must not be taken as a given, as there are very good reasons for the depot I am thinking of to retain such knowledge (which I completely agree with) for the sake of of diversionary activity, be it planned or adhoc in relation to disruption.
These matters are far from black and white. Far too many times (in my time) there were occasional initiatives to save £££ by this or that means, ie cutting back on route or traction knowledge at this or that depot, which then put service recovery in jeopardy.
I am sure those directly involved (in relation to 701 and the consequences of) will be on the case!