Compulsory or not, lets face it, you would be mad not to have it considering the cost. Can you imagine the situation where you were up a ladder and dropped something on a passerby and badly hurt them(or worse!) Victim aside, you could reckon house,car,van, any savings etc, gone, in an instant, and maybe working the rest of your life for next to nothing.
It's unlikely any of us on here understand insurance fully. I was in business over 20 years and never had a problem (I did have claims) but I always used a broker who knew his job. He has retired now so I had to change.
DforDave. I use these people, but they are in Stockport so may be to far for you. They seem OK though.
CCG. 0161 480 0050. I deal with Chris Hall and he's a nice and helpful Guy. Don't really want to put my name on here though. Good Luck.