There is no third letter.
The "Y" in a serial code is indicative of bone china but bone china did not have a three letter dating system, only earthenware did.
Anyway great site thanks for letting me join.
Whether you have it repaired or not is really dependent on the venue you choose to sell it in.
The first and last one definitely sound real.
Any thoughts on the dating of this? The pot itself has light crazing with some discolouration and and there is a little roughness to the rim of the spout.