Status update...
Well, I finally got it going last night:
1. Set up the ad-hoc relationship
2. Checked to make sure the MA101 was broadcasting using WifiFoFum
3. Tried to connect.
4. I finally connected by explicitly specifying an IP and trying the connect a number of times
5. I then tried turning on WEP - all good :)
Now, this should have been the end of the story however:

i) After 10 Minutes the Connection Dropped and I could not re-establish connection
ii) Before you ask - yes I did have the MS Wifi Zero config service disabled ;)
iii) Upon attempted reconnection, I recieved the "Your Wep Key doesn't match" icon on the Dell Wireless Utility...
Still Confused, but at least I now know it does work! :D
I'll keep trawling for more answers, my final goal being to be able to return home and just connect, which at the moment seems a little ways off yet...
-- Dan :rolling: