You won't find any offshore guys without an IR these days. Capt/SFO or FO.
Salaries range from around £60k for FO up to over £100k for senior offshore captains and more if they are TRI/E etc.
Onshore Corporate Captain, IR, Multi crew, £75k.
Certain organisations pay a lot more for an experienced Corporate Onshore Captain, these range from £85k-£100k+ and will include a pension, usually health benefits and sometimes a car allowance. The good ones that is. The bad ones will pay whatever they can get away with.