Post update from later in the day. Ok, so I have established it was the old skin that was causing the problems. IN the old wordpress skin comments work fine. Be aware I am going to play about with a new skin over the next 24 hours and who knows what will happen then!
Again, if you are having any problems, please email me at xxxxx as I don’t know what the problem is until someone tells me. Thanks! 
Earlier …
Someone has brought to my attention there may be issues with posting comments. I’ve made a few changes in the admin panel, so if you are still having problems commenting please email me to let me know.
Ach, this technology. Gardening is easier!
……
Nope, people are still having problems. I have reverted back to the basic wordpress skin and have removed any commenting impediment I can see within admin … so let’s see if this works …
If anyone manages to post a comment I may go giddy with excitement!
(Well, *I* can post a comment but I hardly count. LOL)