Closing line stations, I don't think so. I think this may have more to do with the fact that IAG [the overall parent company for BA/IB/VY/EI] is doing a Company wide review [of all the departments of all the Airlines] In engineering or the MRO division as IAG calls it they are only 5% through this review [looking at whether current set-ups provide "best-value" etc]
The "rumour" flying around line stations is that they want to get line station staff onto IAG contracts [this has been raised in the past but then went on the back burner] So if that is what they are wanting to do again, then yes technically the staff would cease to work for BA and then work for IAG.
IAG have already done this in some areas with new managers in BA Cargo going straight onto IAG contracts and as line station engineers are TMG [Technical Manager Grade] there would be no reason they couldn't do it to them as well.