There seems to have been an election or agreement in place, not sure which, whereby you have paid the employers NIC on the Options.
It seems from the guidance, that as the employer was required to operate PAYE, the employer should have taken this into account when calculating the tax due.
Please see the following guidance.
ERSM30490 - Restricted securities: relief for NICs elections and agreements
ERSM110520 - Securities Options: deductible amounts: employer's NICs met by employee
NIM06813 - Class 1 NICs: employment-related securities: shares: employee agrees or elects to pay secondary Class 1 NICs
If that's the case, then there is nothing for you to claim.
The adjustment should have been done by your employer as part of their PAYE calculations and you should speak to them in the first instance to check whether they have done so and if not, they should advise you why not.