Wow. Thanks again for all the helpful suggestions. I may try regrinding the iron (it says it should be at 25 degrees on the iron itself). However, even though this plane is more than a decade old, it has never been used, and the iron will be as it was shipped.
I should explain that the plane was bought brand-new for me maybe 15+ years ago. However, it was around this time that children arrived on the scene and I found I had no real time for woodworking. In addition, I was more of a 'machine' guy (too much Norm?) and I rarely used things like hand-planes. Whenever I tried using them the results were pretty awful since I had no idea what I was doing. Kids have moved on, and I have retired, so I am trying to sort out my workshop again, and part of this plan involves getting more familiarity with hand tools and so on. The amount of info on You Tube is incredible (if variable in quality), but the stuff that chaps like Paul Sellars produces is quite inspirational.
So, to respond to some of the comments I have had:
1) I could regrind the bevel, but, as I say, it is in new condition and, since I have never done this before, I may make things worse. I now have a honing guide and I will try to regrind/sharpen some time this week. I'll watch a few You Tube videos first though
2) I don't think there is anything wrong with the lever-cap cam (as shown in that Paul Sellars blog page). I have taken a photograph of mine and it does not look to have the 'B&Q issue' that he mentions. But what do you think?
3) I went through the Sellars set up video again and tried to copy what he did as carefully as I could. With the addition of oil, I think the set up did become a little easier and things didn't seem quite as 'gritty' as they had done before. I advanced the blade and adjusted with the lever such that equal amounts of blade seemed to be sticking out of the plane at each side, The blade seemed correct to me. Then I backed off the blade a little and (with pencil underneath the toe so that the blade wouldn't catch), I tried maybe 4 or 5 advance/retract actions. The lever cap had slid, as you can see (the blue line was put on after set up and was hard against the screw prior to the adjustment and advance/retract actions):
Interestingly, even though the blade was aligned correctly 'level' with the sole (apologies if I'm using the wrong term), it was not remotely parallel to the mouth. See:
Please excuse the blue lines. These were put on when I had a mad idea of trying to flatten the sole (as per some videos I have seen). But I was undone somewhat by the lack of a long-enough flat surface and a shortness of sand-paper :shock:
I would like ot try to get this working, but I wonder if it is just too 'out of whack' for a beginner such as me to put right.
Thanks again for the interest and suggestions. I have learned a great deal from them.