Cheers for the help guy's .... I will wait until I finish work, then throw myself into getting it textured somehow...
Trouble is, there are tut's on the net for metal textures, but all the ones I see are for 'brushed aluminium' or other 'pretty' type metals... Not the grungy walkways I require.
Thanks for your comments 'M' I have now cut the offending pointed roof out, but don't really understand what you mean by the 'Overhang?' of the passages...(tubes) I will post another pic soon so you can see..

Regards Scraggy