Off the top of my head, either some entirely internal process designed to kick the issue into the long grass, or some entirely made up bollox designed to make you lose the will to live.
The bottom line is that they have negligently injured you (damaged your property) and you are entitled under the law of tort to be made whole (be appropriately compensated).
If there is some alternative process, other than suing in the county court, that is beneficial to you (e.g. if there is an Ombudsman that will hand them their arses on your behalf - which I would assume there isn't), then it might help them to tick the appropriate boxes to that process.
Unless Openretch (no longer called BT Openretch, but still wholly owned by BT) have told you that Keoghs is their address for service, Openretch @ <Openretch's registered address> is the correct address for service. However, it may be prudent to follow up on your original complaint to Openretch asking them to confirm their address for service (effectively a nudge before letter before claim).
There is an expectation that both parties will behave reasonably, which arguably includes not going straight into threats of litigation - although the letter before action (which is very much a threat of litigation) is the only mandated step. For the matter to be kicked down the corridor to the wife's cousin's hairdresser's catwalker, who then takes the thick end of a month to respond to the effect that they might get around to looking at it within 3 months, but only if they feel like it, suggests that if you try to be any more reasonable, they'll charge you extra for the vaseline.