About work permits - It is very VERY difficuly to get a work permit. There are two ways you can do it:
If you will be working for someone else (or can get someone Turkish to apply for you) you need to get copies of all relevant certificates and your passport, have them certified as true copies by your solicitor (any high street solicitor will do this for around £5 per cert), then send them to the FCO at Old Admiralty Buildings in London for legalisation. That costs around £13 per piece of paper plus p&p - It takes AT LEAST two weeks. You then forward all of that to the person applying for the work permit, and at the same time apply to the Turkish Embassy for a visa. Eventually (It took me 6 months) if they agree, you turn up in person in Lodnon to collect and pay for the visa, while your employer in Turkey gets the work permit. He then has a duty to make NI contributions here (reciprocal agreement with UK) and to get your health insurance etc etc. It is very long winded, and it costs the employer around $750. Your employer has to prove that you will be doing a job no Turkish person can do (which unless it's something relevant to a native-English speaker if very hard).
The other way to do it is if you set up your own company here. This costs around £600, and as a ltd company there are fixed rates to pay your accountant (250YTL month) regardless of whether you have any invoices or not, plus you have to pay your insurance (150YTL month for basic one). You can register a business in a rented place or use your home address. It takes around2-3 weeks to do this. You can then apply for a work permit to work in your own company. It costs the same as above, but you have a 90% of being granted one as it's your own company - otherwise you are entitled to own a company but not to work in it!!! If you don't have a work permit you have to emply someone and that costs around £500 a month with insurance etc. The KDV rules are a bit of a minefield too, so you need an accountant who can speak English. Work permits still take around 4-6 months though and in that time you can't work (officially).
I went through all this just to teach English!
Hope this helps.
Jill