This should not be a particularly big problem, Alex. The control is formerly the village school, and I understand it has a number of rooms (I shall be visiting it in a couple of weeks time, so will have a better idea then). Subject to not detracting from sleeping areas, it should be possible to provide a space for such bags. I doubt it will be guaranteed secure, though.
Eskdalemuir is not one of the designated bag drops (I know that is not what you were referring to). I'm not sure what effect that will have on the number of folks overnighting there. Both Alston (90k before) and Dalkeith (85k after) are designated bag drops, and have better sleeping arrangement than we will be able to provide at Eskdalemuir. We have no showers, and apart from some blakets being available it doesn't appear we will have anything other than some floor space. We'll be doing what we can, though.