@ajc153 I'm no expert in networking but it sounds like you may have a couple of basic configuration problems. Daisy-chaining routers will cause problems on the network unless you disable DHCP and NAT on the down-stream slaves.
The ideal option is to eliminate the extra routers all together. If for some weird reason you can't (and remember lots of other people are running Vodafone TV on simple setups without having the issues you speak of), then for reliability and performance my suggestion is to:
a) Disable DHCP and NAT on the two(?) slave routers so that only one upstream router (closest to the ONT) is doing DHCP and NAT.
b) If you can't disable NAT, then plug the slave routers in the master (the one closest to the ONT) using the LAN ports, not the WAN ports.
Ask a silly question but is your "incompatible with V.F." Wireless AP set to a New Zealand channel range? If it is dynamically changing to a wireless channel that is restricted in N.Z. (such as Ch14) the V.F. TV will loose the wireless connection. You might want to try setting it to stay on channel 1, 6 or 11.
Quick note I only two routers for a couple of days, only the vodafone is running now, maybe have a quick read of my long post with the full history. Im not using the Vodafone TV wireless, its connected with cat6.