So, that's it. Southeastern will be back in their normal places as of tomorrow.
I gave the Waterloo to Dover service a run on Thursday. It was certainly a nice change of scenery to straddle the South Bank of the Thames up to Battersea. The Linford curve was nothing particularly special, but did its job. The running time from Waterloo up to Linford was probably not that different from the time it normally takes leaving Victoria and navigating the points and the incline up to Grosvenor Bridge to the same pont.
It was only the awkward routing via the Catford Loop and then getting stuck at Lewisham Vale whilst waiting for several Cannon Street trains to go through that slowed the service down. A friend of mine made the same journey at a different time, and due to problems at Lewisham, his train was routed via Bromley South not stopping, and this was apparently a lot smoother.
Also to Southeastern's credit, they were very quick to preemptively divert the service to run to Blackfriars as Waterloo had several signal-related issues throughout the week.
All in all, this temporary change of home to Waterloo felt like an experiment more than a necessity - "we'll give a try because the option is on the table and it hasn't been done before". Whilst I see little point of having regular Kent services to Waterloo Main, it certainly does look viable in the future as an alternative during planned engineering works or other times of disruption. At least, perhaps once they've re-opened the international platforms again.