Thank you Jack. Yes it does. They certainly do facilitate adjustment , but I was thinking that I had assembled it wrongly in that I thought the blade was some how sprung loaded to have a bit of give if it hit something hard, but they didn't seem to do that. I was thinking back to an old mower , a Villiers I think, that had a sprung bottom blade as a bit of a protective device.
I am not doing a full restoration by any means, but have cleaned it all up, getting everything working, and hoping to have my first mow within a week. I bought the mower not going and am having a lot of pleasure in seeing the quality build as I work on it.
Will add a photo or two later. Thanks once again.