I have a couple worries about when I first arrive back in the UK
Is it possible to open a bank account when I get there, what is needed to open an account?
Also is it hard for foreigners to get a job? (even though i'm British I'm still a foreigner to them)
How do I go about getting NHS?
Also driving I know I can drive for up to 6 months on my current drivers license before I have to get a UK one?

Yes, the usual requirements are proof of address and proof of identity

Generally, if you are willing to work hard and make a few compromises to get your first job here, then it shouldn't be too difficult to find paid employment. If it doesn't suit you it is always easier to get a new job when you have a job already. However, if you are a professional, the impact on your career will depend on your profession and where you are in the country.

if you are a British citizen then you qualify for NHS treatment the day you arrive if you are intending to live here permanently. When you have somewhere to live, register at your local GP surgery - you will probably need proof of address and proof of identity/citizenship, ie your passport.

IT's generally 12 months. Have you consulted the DVLA website?