Yes, I agree, the two cases I quoted at Boston were literally on site, with the controlling box at the end of the crossing.i don't know the location of the box at Driffield in relation to the crossing, but the supposition seems realistic.
Incidentally there were two further level crossings at Boston between the two mentioned,ie Locomotive Street and Broadfield St. Neither were manual, both under the control of a crossing keeper,and at both site rail operations were intensive, there being a dozen or more tracks involved, 2 main lines, a goods loop and access to and from the goods yard and motive power depot, plus 8 or ten sidings.Road traffic could wait hours at both. The habitations being otherwise cut off by road.