By David Milliken LONDON (Reuters) – More than 2,000 trucks have been stuck in a queue of more than 20 miles to get to the British port of Dover, the main route for road freight to mainland Europe, due to disruption to ferry services and customs operations, hauliers said on Friday. P&O Ferries, which previously accounted for a third of capacity at Dover, suspended operations last month after an attempt to replace 800 staff with lower-paid workers led to criminal and civil probes from UK authorities. Other ferry companies now say they have no spare capacity until Monday due to demand from holid…