Either of the blast pens would be a rather long job old chap, even if taking short cuts, but fairly simple to make.
PIC 1 appears to be a sand bag wall surrounding either a second, stone block wall, in that mellow Maltese stone, or rectangular, 4 gallon petrol cans, filled with sand.
PIC 5 is a double, spaced wall of stakes and 'wrinkly tin', filled with rubble and sand, not unlike similar structures found on Luftwaffe fields in France.
PIC 6 is a wall of sand-filled petrol cans, probably backed, on the outside, by either a sand and earth bank, or another 'wrinkly tin' fence.
The stone blocks and stacked petrol cans could be simulated from moulded 'sheets' of plaster, modelling clay or putty or similar, or from carved faomboard, as a 'face' for a thicker backing, and then dressed appropriately, whilst the 'wrinkly tin' pallisades could be made with model railway plastic sheet mouldings and rods from BBQ skewers, with a false top dressed with 'rubble'.
I made a typical Fighter Command blast pen, many years ago, with concrete and earth/grass banks, made from cardboard formers covered in scenic materials, and a inner wall of sand bags made by scribing and moulding scenic modelling clay for the smaller sand bagged areas, and carving foamboard for the main walls.. The finished article looked very authentic, but even with the 'short cuts' employed, it took a long time to do.