Upgrade 3.5ton Horsebox ?

[maginn]

I am looking into purchasing a 2-horse lorry, but am worried about being overweight, as I will sometimes have to carry 2x 16.2hh. I have heard that is is possible to upgrade to 3.9 ton, & that this only costs a few hundred pounds, which is well worth it in my view.
Can anyone offer any advice on the procedure for doing this and also would the lorry then have to go through a plating rather than MOT ?
Thanks

 

[ihatework]

I know the renault masters can be upgraded but I'm afraid I do not know about other makes or how to go about it.
But yes I believe the lorry will need to be plated once upgraded, in addition I am not sure if it can then be downgraded afterwards which might affect its resale value given that these boxes are popular as at 3.5T anyone who passed test after 1997 can drive them without taking an additional test.
You might be better off looking for a 5.5 -6 T compact box if you want to take 2 x 16.2hh on a regular basis.