Suspension height

I'd be concerned about what that weighs, if it's sat that low you could very easily be over the maximum authorised mass. Also if you are towing with it your trailer nose weight won't help if you are close to the M.A.M. You could always get some stronger rear springs to level it up but that won't help if it's overweight.

I suspect the problem is not the weight, but the position of the weight.

Normal passenger and luggage weight is on the axle or slightly forward of the axle.

Some of your weight, based on the picture is behind the axle. The more distant it is from the axle the more effect it will have, remember the principle of levers from school physics.

The weight in that rear box is perhaps 0.7 to 0.9 metres from the fulcrum (the axle).

I stand by my earlier comments. The simple fact is that even though you have removed weight from your car you have obviously added that weight and more besides otherwise the suspension would be sat in its intended position. You really need to get that on a weighbridge. Then you can always argue with the law that for all it looks wrong it is within the limits. The police and or a vosa check point can't tell just by looking exactly how heavy a vehicle is but if it looks wrong then they have probable cause to have a word.