Thanks for the reply,

I've read throught your links and have a few questions. Am I right in thinking that the root bridge should be at the centre of the network as it is used in calculating the least cost path across the network?

Also, I'm thinking of using auto edge instead of bpdu guard as the bpdu guard requires manual intervention.

We had a network issue in the past, where I suspect our ISP changed spanning tree costs and caused one of our switches to go down - I've  seen the option to enable root and loop guard, but the problem is that if I did enable this on our main uplink to our ISP, with this setting enabled, all that would happen (if I'm correct) is that our main uplink would fail.

Any tips would be appreciated - thanks in advance...