Both LEDs flashing means the SIM is not able to communicate with the network.
I would try performing a manual network selection with the 3G SIM in a phone. Select another network like T-Mobile or O2.
The phone will then warn you and advise SOS calls only, thats fine.
Repeat the manual network selection and this time choose Vodafone.
Basically, what you're doing is you're jumping off the network and then back on again to update the services on the SIM.
If this fails,
I would start by trying to connect to Vodafone live (WAP) if possible from your phone.
This will confirm GPRS/3G data is definitly activated on your SIM.
If this is not possible, it may be due to lack of coverage in the area.
Try another location and call Vodafone to confirm coverage in area, the SIM is active and is on the right data tariff.
You can also check vodafone coverage here:
http://maps.vodafone.co.uk/coveragev...b/default.aspx
If after all this its still not working, the ExpressCard itself maybe faulty.
Have it checked out in a store.