Whickerman, you are a very lucky man to work for a company that appreciates you and what you do, I would stay where I was if it applied to me, happiness and contentment can't be bought by a higher wage, you will have more stress, be away from your family, be given unatainable targets that rise every few months, the stress will get more, you will worry, arguements at home leading to more stress leading to more arguments, unless you like being stressed of course.
I left London 28 years ago, I was earning good money, approx �200, per week then, which was very good, I moved to North wales earnt less than half but was so happy, quality of life is more important than material gain, I spent so much time with my children, that was priceless, good luck to you what ever you decide, just remember a good boss is hard to find, with the big company you will not be a name, you will be a number,
Ray