Tony, plenty of people around here have made same very simple but effective benches. Paul Chapman's was the inspiration for mine.
Here is my interpretation of the the "Chapman" bench. Not the prettiest bench in the world but I think will be fit for purpose.
M&T frames
MR chipboard flooring for the shelf, kitchen cabinet adjustable feet in two rows of four prevent sagging. Rails inset and screwed to end frames. The back is also MR chipbaord flooring. 1" chipboard desk top (no longer curved) as sub base for the the MDF bench top.
bench top is 3 18mm mdf individual beech lipping. Top layer MR due to availability. Glued and clamped without biscuits or dowels.
Dog hole drilling with mortiser and wood beaver bit. The holes were then "countersunk" using a Trend T10 router and small guided round over bit. Thanks to DaveL for the suggestion. I took a deep breadth, practised a few times first and I am very pleased with the result.
Top finished with cuprinol wood stain, to cover up the horrid green, and Ronseal diamond hard floor varnish.
Holdfasts from Richard T (UKW). First time I have ever used and boy are they incredibly simple to use and effective.
I have no plans to add any vises as I have a face vice on the Sjobergs bench
I will probably screw it to the floor but must rearrange the workshop before the bench finds finds it's final resting place.
Andy