if you know someone at work who is handy with the tools then I'd say it's worthwhile taking it down. - in any case you'd have to probably drive it to a garage to get it fixed anyways!
As long as it doesn't sound like an engine noise i'd say you're okay, just take a peek under the bonnet tomorrow morning and make sure your engine isn't actually falling over! - but if you upper mount, lower gearbox, and new dog bone are still ok, then I really don't think the upper gearbox should be causing you as much pain as you seem to be experiencing.. btw, the upper gearbox mount is dead easy to change yourself. Just get it for £15 off eBay, support the gearbox with a jack, take the battery off, 3 bolts and you're done. - just make sure you hold the two smaller bolts in place when your loosen them so they don't fall through and loose them forever. - but you do need a deep socket set.
A better description of the noises would be useful !
