Kenny,

I second what Anne said about swimming. I started out last summer near the weight you are now and swimming was the best exercise for me at that time. These days, I'm doing a lot of walking because it's so easy to schedule a walk into my day, but walking more than a mile or so was difficult until I got below 325. I still try to swim at least once a week.

Swimming is time consuming, but it is worth it. It exercises all your muscles, is good for your heart, and is easy on the joints for those of us who carry a lot of weight around. Do you have anything like our YMCAs or community centers/pools in England? You shouldn't need to join an expensive health club just to get access to a pool.