Loan agreement possible before transfer for land registry exists

The whole thing should be unproblematic for you. As already discussed here, the properly registered priority land charge is merely a disbursement requirement. For the credit decision, banks, of course, request land register excerpts, since there could also be value-reducing rights recorded in the land register. However, I do not assume that to be the case given its current use as agricultural land. The current land register excerpt (before surveying) should be available to you through your purchase contract and can be forwarded to the bank.

If the bank wants to register the land charge immediately, this is theoretically possible. Simply put, it would then refer to a part of the existing overall property that still needs to be surveyed and mark the area that will belong to you in the future. In my opinion, however, this is absolutely unusual in the private customer sector.