Thanks for all the feedback on the various shoes. I learnt that not all sizes are equal. Brooks, NB, Asics, Montrail and Salamon don't fit me in a 12 whereas Saucony do. Very few places are willing to buy in larger sizes for you to try out; they expect you to buy them without trying them.
With persistance, Up & Running (Leeds) sorted me out with Saucony Approach. I took them for their virgin workout this morning in appalling conditions. They were excellent in the wet and mud, and keep the water out well. Only slips were on wet and slightly muddy grass at an angle when I slipped to the side twice.
The ride was comfortable. I can recommend these for the heavier, larger footed runner who needs a trail shoe for muddy conditions.
Thanks everybody. I'll let you know how long they last!
The Shire Horse