[Sharky1973]

A dive master internship is a great idea; you will get real hands on experience and be able to work alongside different instructors which will provide a real understanding of the job. The minimum it will take is 2 weeks, but a couple of months would be better. You will gain invaluable experience of assisting with different courses, and be able to fun dive as much as you like for free! Koh Tao in the gulf of Thailand is incredible, and i would have to say that Buddha View Resort is definitely the best in my view.
If you take a look at Dive Careers Koh Tao | PADI Scuba Diving and Diving Instructor courses it will list all the prices and what they offer. All the instructors there are incredibly friendly and helpful and the course director Mark Soworka is fantastic, and experienced beyond belief!! You would definitely be in safe hands and I promise that you will have an amazing time. They also run IDC courses every month.

I do agree that another language is useful when looking for employment, but as for earnings everything is relevant, so although wages compared to the UK are low, you have to realize that the cost of living is also a lot lower and saving is possible.