It should be standard issue now, but early adopters and international importers may have missed out. For the record, here is the Pashley Guvnor Maintenance Kit.
It comprises:
1 x 6mm Allen key
1 x 13/15mm spanner
25g of Brooks Saddle Proofide
100ml of 3-in-1 oil
1 x spare inner tube
125g Guvnor blend tea