Catastro plan and Escritura worng

Hi, I have just been loking through my paperwork in order to help a neighbour change her Catastro plan as hers is incorrect. I have now found that mine is incorrect and that the Escritura does not reflect the contract we signed.

With regard to the Catastro plan ( if the Deeds were correct, like my neighbours are) is it a case of sending modelo 901 N to the Catastro, with a plan signed by the original seller and the owner now. There is no dispute eith the original owner that a small area of land should be included with the neighbours title in the Catastro plan.

Moving on to the Escritura that does not conform with the Contract. The contract ( with plan attached ) confirms 1200m2 but within the Escritura the land is described as 1000m2 and I can see a form from the Ayuntamiento that has only segregated 1000m2. Also water rights were included in the contract but they have not been passed on in the Escritura, Again, the original owner that sold to me would not dispute any of this but at the moment he owns my swimming pool and I own his pozo and vegetable patch ! Can a document be drawn up to sign in the Notary to confirm the original Escritura was incorrect ? Presumably I wouls have to have the Ayuntamiento agree to segregate the additional 200m2 first.

Any advice would be very much appreciated.

Becky