Hey bro. I think you've got some great motivation already.
I sat down with my GP the other day and did a bit of mate, and we worked out, that I lost an average of 2kgs a month over the 2 years I was losing weight. Realistically though some months I was literally able to lose 5kgs a month, but I'm not going to lie that was being completely dedicated to the cause. That was training for 1.5hrs (not solidly unless it was a cardio night weights nights was rotating with 3 people) 6 nights a week. 3 weights, 3 cardio.
As said before, no crisps, fizzy drinks, fast food, sugary treats, that kind of thing. We've chatted about this before
You don't have to do the boring meat and 3 veg every night. you can mix it up, make casseroles, stir fries, meat and veg curries, that kind of thing and you'll always have something fun and different to eat.
Are you still leading that hectic work schedule that sees you home well after 8? Because I completely squashed eating after 8pm too (other then protein after the gym), because that is when your metabolism starts to slow down.
I think we are all willing to help you any way we can to meet your goals. I'd love to see you drop the 3 stone for your wedding, I think it'd be awesome, and is completely doable.
Another way to get motivated is to find a mate that might be looking to lose weight, or someone that is already training and train with them. That way you feel obligated to work out. Oh or, how about teaming up with your girlfriend, I'm sure she wouldn't mind being a little fitter for her wedding day, maybe she would like to work out with you? Make it a team effort. Just be very careful how you word it, or you might not have to worry about losing that weight

If you need any help with anything at all let me know mate, and I'll do my best. If you were local to me I'd be dragging you sorry a$$ with me to the gym, no excuses! haha.