GB isn`t BA. Its a totally different company. It isn`t even BA owned. GB Airways is a BA franchise, that is they pay BA is use their colour scheme, interior, sales and marketing, product etc.
Yes the drinks are free on board, but its hardly going to effect salaries that much. They do sale duty free.
I believe GB are offering perm. contracts?
Don`t base you salary on a liquor bar sales. You need to look at terms & conditions, basic and flight allowances. Duty Free sales commission are unreliable source of income, always have and always will.
GB are a good company and fly some great routes with some very nice nightstops.
If you were looking to join GB in a bid for easy access in to BA then you were applying for the wrong reasons.
If your happy where you are thats good and I`m pleased for you.