Have you viewed their video and could it be posted here?
Is unclear signage enough?
The legal test is:
Traffic signs
18.—(1) Where an order relating to any road has been made, the order making authority shall take such steps as are necessary to secure—
(a)before the order comes into force, the placing on or near the road of such traffic signs in such positions as the order making authority may consider requisite for securing that adequate information as to the effect of the order is made available to persons using the road;
(b)the maintenance of such signs for so long as the order remains in force
Prescribed traffic signs(under the Traffic Sign etc. Regs) form part of this duty, but not its totality. Where, as here, the regulatory signs are placed such that they cannot be seen and read before a driver has committed themselves to their manoeuvre the presence of advance 'warning' signs is an important consideration.
So, definitive evidence of the presence or otherwise of advance signs is important. GSV is no help as it's too dated.