This service is offered by 'LP Rails':
www.lprails.co.uk
You will see from the introduction on LP Rails site, that the servicing of Farish product was at one time operated by 'BR Lines', which business remains active in spares supply: there is a link to this business on the LP Rails site which further explains the history since Farish was purchased by Bachmann.
LP Rails – Bachmann Authorised N-Gauge Repairs Specialist

You will see from the introduction on LP Rails site, that the servicing of Farish product was at one time operated by 'BR Lines', which business remains active in spares supply: there is a link to this business on the LP Rails site which further explains the history since Farish was purchased by Bachmann.