New Visa And New Passport Combo Question

i hope someone can help with this, its getting very close to when i need to make a decision by...my situation is this: i presently have a non imm b visa without a work permit and require a new passport (UK) and also a new non imm b visa with minimal documents (not a transfer of visa but a new one), my last visa was obtained using a letter from an employer here in Thailand, the same can be obtained...so basically im looking for the cheapest option, but i think i would be better off, if i apply for my visa with my new passport which means that i need it issuing in a country other than Thailand.

can anyone suggest to me where i should go to sort out both my new passport and my visa, bare in mind, that i would only have the one document with me in order to gain the non imm B visa.

many thanks

Ben