Well folks,
I got speaking to Customer Service with Nokia, and a Technician called me back. He told me some things to try to see if it resolved the issue of " No Gateway reply " and also " WLAN Network not found " even though your right beside the router !
What he told me didnt fix it so I rang back and got put through to another person in the technical team. He explained there are only two reasons as to why " No Gateway reply" or " WLAN network not found " can appear on the handset
1) Your access point settings, usually these should work automatically ok when you connect to a network hoeever two things in the access point setting can cause the error messages .. the first being the WEP key - if you enter it incorrectly, and secondly and more likely issometimes you need to define the " gateway " itself in the advance settings of the phone. This is in the connections - access points - " YOUR ACCESS POINT " - select " options " on your network name - this will take you to advance options and then select " IPv4 settings " this will allow you to assign your fone an IP address and to also enter the gateway IP from your router ( usually something like 192.168.1.1 )
if this does not fix it !!!
2) As in my case nokia have said I have an " intermitten antenna fault " in my handset, as the fact it has connected at all and then wont, and wont connect to any other networks is a fault.
Im getting brand new handset swap delivered the day after tomorrow so hopefully that will work fine.. I told nokia a lot of people had been having the same problem about " no gateway reply " and he said they can usually fix this within about a minute, as its to do with people not setting their N95 up correctly with their BT homehubs.
Hope this posts helps some people

All the best
Paddy C