lease note the application number is either prefixed with a P, N, R, A, F, FE or EL.
e.g.
P12345 = Full Plans Application
N12345 = Building Notice Applications
R12345 = Regularisation Applications
A12345 = Initial Notice Applications
F12345 = Self Certification Notification
FE12345 = Self Certification Notification
EL12345 = Self Certification Notification
You do not need to enter the full number if you do not know the last part