Exceeding 7.5t Weight Limit

i drive a 44t wagon and drag and 75% of my work is household effects all over the country and i obviously come across these problems daily but when you have to get to a house in the middle of a housing estate whats a driver suppose to do ? i have also been fined for entering the london timed weight limit area at 06:37 one morning on the A21 at orpington and even though i display an exemption permit in the window i was still fined £120 ( reduced if i pay within 14 days to £60) and the boss got a fine for £550 ( reduced to £225 if paid within 14 day) so why the hell do they insist on these permits if you are still going to stung anyway !!