I think what Brian really needs is something painted in the *road*. If Brian knows a local with a hoody, just an arrow in the road with "Brian's Gaff" underneath.
For something more permanent perhaps a sign on the same pattern as diagram 544.2 but larger, in white and with an arrow pointing to his gate. The council could be sold it as a test of what might be useful for others.
For Brian: diagram 544.2 is a warning sign for road users showing 2 people in outline, one with a stick. Its general meaning is "Frail or disabled pedestrians likely to cross road ahead" but it can have a plate saying "Blind People".