Just a quick follow up. I've now tried a whole bunch of different speed tests and I'm beginning to suspect that the OOKLA app is the dodgy one.
Using my laptop, all agree that the speed squirting out of the patch cable is between 145 and 165 mbps. Using the telly, OOKLA says between 18 and 25, Netflix's own diagnostics is consistent at 33.5, and all the other web based tests (I tried 5 different ones) returned between 65 and 108.
Netflix is looking at its own streaming servers and that's probably what its app is using. As all the other web based apps returned a far higher result than OOKLA I think that it (which is a beta in any case) is probably not playing nicely with WebOS and the television.
Bored now...
EDITED: 18 Jan 2017 19:22 by WILLIAMA