After a little more digging.
22DISK can copy with this format, although the existing format specs do not seem to include exactly like. However, there are 80 track DD, and there are 5 x 1024 byte sectors. So could create one to read this format OK.
Looking at other files in the .RAR, there does not seem to be any problem with sector interleave, but maybe just not on the files I've checked so far. Looking in 22DISK, the 1024 byte sectors seem to tend to interleave, so the sector numbers are 1, 3, 5, 2, 4. Whatever software created the disk image files may - or may not - have adjusted for this? Need to do a bit more research about this, just extracting the files according to the calc noted earlier could produce garbage!
Not sure, but I think that one of the image progs I have will write a raw image (as opposed to it's usual format), and the PC that's on has a 80T DSDD drive, and once the data is on a CP/M format floppy then 22DISK can be set to read it as a CP/M disk and can read/write/copy etc the indiv files.
More of a problem, mind you, if you need to create a disk that will work correctly on a Robotron PC 1715 (is that right ?) as that will need the format to be exactly so. Is THIS your intention?
Further to my previous interest in the dBase there, I note that at least one other disk has dBase on, correctly named, not deleted.
Geoff
Although it is nice machine, I can not/do not want have everything 
