Specialist commercial vehicles, eg refrigerated vans, vans for specialised purposes, sign written or fitted out for a specific commercial use may be considered on a case by case basis.
Gellir ystyried cerbydau masnachol arbenigol, ee faniau oergell, faniau at ddibenion arbenigol, arwyddion wedi'u hysgrifennu neu eu gosod ar gyfer defnydd masnachol penodol fesul achos