At that time, I would have been living in Fareham and recall that there was an interchange for the outbound Triumph naval weekend leave services, in Harrison Road, Fareham, at the back of Price's Grammar School playing fields.
On Friday late afternoon/early evening, Southdown coaches would arrive from Pompey, Gosport and 'stone frigates' (land bases) such as HMS Collingwood. Sailors would swap coaches for their final destination. When all transfers were completed, a stream of coaches would roar off around the right-hand bend of Harrison Road, sharp left into Serpentine Road, up the hill and bearing left before turning right into Park Lane, then onward to their destinations. On more than one occasion a coach would miss the gentle left at the top of Serpentine Road and, shortly thereafter, come to a screeching halt in the cul-de-sac of Mead Way.
I assume there must have been a similar interchange point for return services on a Sunday evening, but where this was I never knew.
Before my time in the Express Services office, I had spent a year at Portsmouth. During that time I had conversations with drivers on the Triumph express services and I never heard any talk of a similar arrangement on the return journeys. In fact it would have been very difficult to arrange with coaches coming back on five main routes; Bristol, Leeds, Liverpool, London and Plymouth. What did happen was that the coaches on one of the routes would get together even though they might have different starting points. For example, the Liverpool route would have the regular driver starting from there, one from Manchester, possibly one from Newcastle under Lyme and at least two from Birmingham. I think the drivers would sort out their passengers so that each would have the least number of 'ships' to drop off.
I was told that frequently the sailors were often amenable because they were the worse for the odd drink or several. There was one occasion when a coach returning from Leeds had its rear run into into Northampton, crushing the back seat. Fearing the worst, the driver went to the back knowing that a sailor had been sitting on it. It turned out he had been stretched out, asleep. The collision had rolled him off onto the floor. He got up, a little bit groggy, sat down again and promptly went back to sleep.
There were other events that even given the length of time mean that the participants are probably no longer with us, perhaps should not be put in print.
Edit: removed inadvertent double-quote