Thanks guys for your help

PhilC - tried that but with no meaningful result - I may try this on other .obj imports

geogress - Thanks for the download link - tried Twoface and it appeared to work unitl I rendered the object and then got a chequerboard pattern :-o

so...

Thanks to nruddock for your tip on 'normals forward'  -  did that on the 'twofaced' object and it worked!!  (Incidentally, this didn't give a good result on the original single sided figure!)

Once again, thanks guys!!