Not LGV but an EU regs question
Vehicle = van 2800 GVW
Trailer = plated at 1000 MAM but with fixed bowser, generator and steam cleaning equipment so the trailer cannot be used for any other purpose
Total MAM 3800 so over the 3500 exempt limit for tacho BUT if the trailer is classed as plant does that exempt it 
I cannot find this sort of set up in any examples so could not give a definitive answer to the person who asked me
No. See Pritchard & DEVENISH V DPP.
Although the trailer may be viewed as fixed equipment the towing vehicle has the capacity to carry goods.
Other exemptions may apply; MAM less than 7.5 tonnes, used within 100 km of Base, carrying equipment for use of the driver and driving not main job.
geebee45:
No. See Pritchard & DEVENISH V DPP.
Although the trailer may be viewed as fixed equipment the towing vehicle has the capacity to carry goods.
Other exemptions may apply; MAM less than 7.5 tonnes, used within 100 km of Base, carrying equipment for use of the driver and driving not main job.
Thank you Graeme 
So …
The total MAM takes preference
The trailer which may be plant does not in itself reduced the above as the vehicle can carry goods
It is less than 7.5 tonnes total MAM
I think it may go more than 100km from base … will need to check that
The equipment is deffo for use of the driver as it goes to a place then stays there all day for the driver and mate to clean a place
ADD - found a radius map and all the work is within 100 km = https://www.freemaptools.com/radius-from-uk-postcode.htm