Hi Great Plum, we have the same problem on the golf course at the moment. If the land is really wet i'd be tempted to leave mowing, as you could damage the soil structure, causing compaction and root break. The more leaf blade you can leave during winter, the happier the grass will be due to a larger area for photosyntesis. Maybe the upcoming cold spell will knock the growth back and you could wait till spring to mow? If you do mow, try to do it on a dry day, with a sharp mower and dont take more than a third of the leaf away. Being too aggressive might stress the grass causing bare patches and moss infestation.