Sorry about the eye problems but at least these days the operations seem to be very successful.
I can understand your frustration about not being able to use the MH - and take dashcams of feckwit drivers on way to Mansfield
Have not seen you post any recently.
As for the MH sitting on the drive, I would not worry too much. For the last 8 winters our MH has sat in our yard in Poland for most of the winter. It is on EHU and I do drain it down. We do not use any heat and nothing seems to get damp, but our N&B Arto is well insulated and even bedding is left inside with no problems.
Your comments about pump and taps indicate you have not drained down, but now by mid-Feb it may not be necessary. As to rust, you are on the drier side of England and I cannot imagine rust is much different whether it is parked or driving on salt-treated roads, maybe better.
One thought is to chock the wheels and release the handbrake. I do run the engine sometimes to ensure lubrication.
We have not driven it for months and recently snow on the steepish driveway has prevented it - unless I took a fast run up it, but then would not see the Mother and child on the pavement obscured by the hedge - no thanks.
Generally I think the MH will be fine.
Has the first Op restored sight to normal? Good luck with the second Op.