It was in the van, everything else in the van is solid. I'd only bought the pump last week and fired it up to check the pressure, thought I'd drained it but on one side next to the bypass outlet obviously had water in it. Took the ends off the pump to see what was inside and accidentally drained the oil, but it looks to be only the one side that water was left in it. Maybe some hose water ran back inside when I've tuck it away.
Facebook'ed Rutland and they'll get the replacement manifold out today. 45 bucks for the part.
It's a new van and I didn't think it was that cold until the central heating condensate pipe froze up, so checked the van and it seamed colder inside than out. It's that cold the brakes are froze on my wife's Golf.