Driving into Lincoln & having to stop to get past a parked tractor when put van into 2nd gear almost no power at all. Dropped back down into 1st back up into 2nd & it picked up as it should. Changed into 3rd same drop in pulling power, dropped down then back up again all ok but then same things happened intermittently til we arrived at site. Doesn’t sound like clutch slipping but I’m not mechanical so just wondering what if anything it’s likely to be eg. Summat serious about to happen with gearbox that should be looked at now or risk continuing tour - hoping to be back in Dundee by next Tuesday - and taking to be checked when back home, assuming nowt catastrophic has happened by then!