For what it's worth I have just emailed the WC enforcement team and copied the police in too.
'Hi All,
I have just driven past the Trowbridge Road end of the HRR works.
Wheel wash in use? Don’t make me laugh. The road is covered in mud; a total disgrace.
I bet the contractors have a good laugh about WC when they’re in the pub after work....'
If anything is done about this I'll let you know!!