Council Tax issue (Scotland)

There seem to be several issues –I have tried googling and cannot find the answers, unfortunately. Can anyone help? I have tried to keep this as brief as possible.

The property I bought in July 2018 is formed of 4 dwellings. A farmhouse and 3 cottages all requiring substantial repairs. The long term plan is to repair and refurbish all the properties for letting as holiday lets.

2 of the cottages have been exempt from CT for at least 20 years, due to occupation being “prohibited by law”.
The other two have been 100% exempt for 6 months, followed by a further 6 months at 50%. Council now wants to place 100% levy on these two (the farmhouse and one of the cottages.)
The cottage has been completely stripped back to walls due to dampness, there are no windows, doors, internal walls or floors, electricity supply disconnected, no form of heating, no kitchen or bathroom.
The farmhouse is being partly used sporadically as an office / storage area, while we live in a temporary caravan in the garden. The farmhouse will also require to be fully stripped out in due course due to dampness, failed wall plates, floors collapsing, woodworm etc.

The Council has advised us to contact Scottish Assessors to have the stripped out cottage and the farmhouse declared as occupation prohibited by law, and remove them from the CT register in line with the other two cottages. However SA have advised that while they will visit and inspect, if the property still retains the “characteristics of a dwelling”, then they will not remove it from the valuations register.

I wish to appeal the Council decision to apply a 100% levy to farmhouse and cottage, but am stymied by not being able to find any regulations that may apply to this.
While I have no objection to paying CT, I do not consider that 100% levy on both properties is fair in these circumstances, as we are trying hard to bring all the properties back into use. The point of the levy as I understand it, is to prevent people leaving properties vacant, which is the opposite of our intentions!

I should add that these properties are in a remote area of Scotland, and we have been doing a lot of the work ourselves. The availability of suitable builders here is problematic, the good ones are few and far between and have to be booked up far in advance. Building materials have to come in by ferry. All of these issues have added to the delays we have experienced in proceeding with the project. We have also had serious family illness to deal with in the last year, which meant we had to leave the project for several months last winter.

Questions:
1. Does anyone know where I might find the relevant regs that cover these circumstances? I understand that the 100% levy is at the Council’s discretion. However, is this a “blanket discretion” for yes or no in all circumstances, or does the discretion extend to being able to look at individual cases? If there is a right of appeal, on what grounds may appeals be considered?
2. The fact that we are living in a temporary caravan onsite until at least one of the houses is habitable. Does this in itself constitute “occupation” of at least one of the properties (say, the farmhouse), and therefore CT is due at the “normal” rate rather than the 100% levy (ie double) rate?
3. It seems absurd that we have 4 properties that are being treated differently for CT purposes. Ironically the two that are declared “prohibited by law” are now in a slightly better state than the one that we have stripped out as they still have windows!
Again, is there anything in law that we can use to argue the case that the 100% levy is not appropriate in the circumstances?
4. Is the difficulty in employing suitable builders, or the fact we had an unexpected serious illness to deal with, in any way relevant?

Thank you for reading, and I hope someone can point me in the right direction.