Geoff,
When I soaked the soundproofing for the first time I cut it out - two straight cuts along the front and transmission tunnel edges and the floor bit comes out. A third cut up the join of the transmission tunnel and the front of the footwell and that bit comes out too.
You now have four bits (two from each side) that you can easily dry. If the remainder is wet then prop it away from the metal and leave a small fan heater in there overnight.
Because the soundproofing is a foam backed piece of thick rubber, when you put the pieces back in, the thick rubber locates itself against its neighbour nicely.
With the carpet and floor mat over the top you'll never know you had chopped it about.
Hope that makes sence.......