I being unduly worried
Probably, yes. As has been pointed out, it's not uncommon these days and at most UK airports where NATS isn't contracted to supply ATC, ATC staff have done met obs for years (20+ in some cases).
As for approach minima and LVPs, I don't think you need to worry. There is no evidence that where obs are done by non-Met Office staff that the quality of reports is significantly different to those done by Met Office staff. In poor wx RVR is done the same way as it always has been and is provided direct to the controller rather than coming via the met observer.