corporate-wage-slave

Yes, the request does indeed need to be made via BA, you can't book it directly with Omniserv. However I would be fairly certain - particularly at this time of year - that the information was duly communicated to Omniserv but they didn't have sufficient staff to meet the workload. The communication process is what it is, and had the OP arrived on any other airline into LHR it iwould be the same procedure and quite possibly the same outcome with them. Omniserv do not have many friends within the airline staff based at LHR (though it's perhaps not as rock bottom as it was a year or so back) and BA staff in particular have found it difficult to get Omniserv to meet the requests made of it. Omniserv is contracted by HAL to provide the service. Service 2 is door to door and a bit more robust since (inter alia) the BA crew will have to wait until Omniserv turns up at the bus and if necessary the captain can radio in a complaint if they are late to arrive, though I'm told that doesn't make much difference. If Service 1 is selected, and there is a bus involved, then BA have no clue what has gone on after the passenger has left the aircraft.