That looks ok to me. They are likely to reject whatever you say, but that unlocks the next stage is where an independent adjudicator will actually pay attention to what you wrote instead of fobbing you off.
If you wanted to go a little harder you might add this:
3. I am shocked by your insistance that a motorist should access a website when they see your signage, as doing so would constitute an offence under section 2 110. (1)(a) of the The Road Vehicles (Construction and Use) (Amendment) (No. 4) Regulations 2003. If you continue to assett that motorists "can check the Wembley event dates on the Wembley Stadium website" in your response, I require you to explain what exemption to the law allows this. I remind you that the Regulation also states:
(2) No person shall cause or permit any other person to drive a motor vehicle on a road while that other person is using—
(a) a hand-held mobile telephone...
If you do not accept that you are wrong about this, I reserve the rght to do exactly as you say and report that I have done so to the Police stating that you are the person who has permitted it.
