hi,you will find that the floor has possible delamination.ours had a 1993 bailey.if you dont know this is the separation of the top layer of ply from the insulation.the floor is made up of about 2inch thick insulation with a layer of ply top and bottom.this will normally happen in most used places ie.door entrance or kitchen next to sink.you can repair it yourself if you do diy.this means drilling 10mm holes 5inch apart in a large square (not all the way through only to the bottom ply)find the bottom and tape up your drill to that depth.this is filled with a two part mix apoxy resin and plugged with wood dowels as you go.tape up all joints underneath first to stop the glue running out of joints,its like water.before you start support the floor out side in the place of delamination,a wood block and 3x2 is ok.when finished place a large poly sack on top of glue,then a heavy weight ie.gas bottle plus spare tyre or tyres.leave 24 hours to set.apoxy resin about