Yup. Bear with me here....
If I was to take a loan secured on my croft (as I am an owner) and defaulted the bank would want to reposess the land. I could (just before they reposess it) let the croft to my wife (or anyone else that I choose). The bank would then take possession of a croft with a sitting tenant.
One of the cornerstones of crofting law is that tenancies are secure. As long as she pays the rent there is no way that they could then evict my wife. Croft rent is pretty low (or should be) as it is based on the value of unimproved ground, all of the improvements that have been done over the generations by the crofter belong to the crofter not that landowner (not just buildings and fences but the fact that it is good green grass rather than the rocks and heather that it was before generations of crofters improved the ground cannot be reflected in the rent). Rent might only be a few hundred pounds a year.
A crofter also has an absolute right to buy from their landowner at a fixed rate (I think about 10 times the rent). Therefore in the above situation my wife can buy the croft back from the bank if she wants or she can stay a tenant, paying a very low rent with total security. Either way the resale value of the croft for the bank has dropped to near zero.
A croft only has value as land if it is vacant.
Sounds complicated but there are good reasons for the laws - particularly if you know about the history.
The crofting commission recognises this and is willing to decroft house sites so you can get a mortgage.
I did this and it was pretty straightforward. I did the forms myself and it didn't cost much (if anything, I can't remember). No lawyers involved except to separate my title deeds so I had a separate deed to give to the bank for just the house site.
If you want to decroft anything other than the minimum area required for a house or for reasons other than a single house then you may find they take a dim view of it and you could be involved in a very long and difficult battle.