Thanks RichardBaronGolf,
Yeah, sorry about the images, still not quite understanding that.
Thank you very much for your note. That sounds pretty reasonable to me. The patches are about 3 inches long, and don't look too bad. I'm in Devon, so Essex is probably a bit too much of a drag to be honest!
I'll try to work out the image thing here, and try to let you know how I get on with a garage when I get around to it.
Thanks