Hi Ron
I don't think you will have anything to worry about. Just explain in a letter exactly what you have said here. Three to four months will be fine, given your previous circumstances. I also think that if you can produce a marriage certificate and a birth certificate for your son it would be very unlikely that you will be refused a visa.
Your accountant's idea of a cash flow forecast is a good one, although I would do it yourself on a spreadsheet rather than paying for it. Every liitle extra like this will strengthen your case. Your bank balance is more than enough to prove that your average income is sufficient to support a family.
Honestly, I really believe that your application will sail through and wish you the best of luck, Let me know if you need any more advice.
Regards
Mr P & P
