Hi, I have just bought an old Ford Transit Motorhome but I can't find anywhere what the tyre pressure should be. It has been stood on the drive for a year, but has recently passed an MoT. I took it out for a drive and when I get to 50 mph it feels like the whole van is sliding like on ice. Having read some posts it might be my tyre pressure but I just don't know where to find what it should be