Hi I am just about to leave the UK for a 12month career break. I am going to make South Asia my last continent on the way home.

On advice from the London embassy I have bought a single entry visa before departure. But backpackig throws all dates off schedule ! Does anyone know if you can buy a new visa if the issued one is never used or if you can get renewals once you are in the country ?

More generally how easy is it to get Asian visas enroute ? Any real stinkers I should watch out for ? Any advice would be greatfully received !
Thanks

Getting visas en route is incredibly easy - main difficulty is if you're time-pressed. Bangkok is the easiest place in SE Asia to get visas for surrounding countries.

Vietnam - if you've already got it, you're locked into the dates you specified. If you can't make it in those dates, you'll have to get another visa. If you get in by the date window, you can extend in country, though it takes a bit of work.

Cambodia - you can get it on the border, but look up how much it costs before you go, and make sure you only pay the scheduled fee. There is a lot of corruption on the Cambodian borders, but if you persist, you'll get it for what you should. Main thing is to insist on getting a receipt (in any situation where you suspect corruption).

Other countries I've experienced - Myanmar, India, Sri Lanka, Thailand, etc, have all been fine so long as you follow the requirements. Getting into Thailand for most nationalities can be done on arrival. For other countries, whatever you need to do in your home country, Bangkok's requirements will be similar, so just find out roughly what to do before you go, and then do it on arrival (tip - get a bunch of passport photos made once you get to Bangkok, as you'll go through packets of them).