In reply to John Workman:
just to clarify
you bought a contract SIM from o2 with the tablet and that should have data on it?
you've inserted the sim in the tablet
switch off wifi (depends on the tablet how you do this)
now that wifi is off it should try and use the SIM card to connect instead
as neil suggested make sure you have signal / data by popping the sim into another device
is there an o2 shop in fort william?