An update:

Thanks to LT, his mate seems confident we can get a visa this week. Given that, we'll fly down to BKK on Wednesday and check into the Citrus Hotel, Sukhumvit 13 Nana Bangkok for 3 nights. It's near the Visa office and will do.
In a spirit of optimism I've booked flights for us to Darwin for the Saturday which should have us in Darwin by 05.20 Sunday morning and me in hospital on Monday morning.

What more can I say other than heartfelt thanks to you all and if you're in the area let me know and we can knock the top of a few cold ones.

LT - PM sent.