Temp. loss of power to radio/ wipers / windows/ door locks power goes then arter a time all works as normal all fuses are o k anyone offer any help please ???

Sounds like your fusible link is going intermittant on you. Here is a procedure at BMWe34.net (http://www.bmwe34.net/e34main/maintenance/electrical/fusible_link.htm) that describes symptoms and how to replace it. The procedures are for the 525i and 535i, but your 518i should be similar. Good luck!