Thought I'd add a little update. I barrelled the beer and let it stand for 3 weeks and have just started tasting it. I used 90g of sugar and I think that might be a bit much as it comes out very frothy and at some pressure, so you have to let a bit into the glass, let it settle, top up/settle and repeat a few times.
Once done though, it's a very tasty pint. Not one I'd have more than a pint or so of a night, but then I don't generally drink more than that anyway to be honest. If it was served to me at a pub, I'd be more than happy so I guess that's a success.
Of course, I'm now looking at getting another barrel and a different beer to brew that's a little lighter than the Nog. I tend to like darker bitters and of late I've been enjoying the odd bottle of Betty Stoggs cornish and Ringwood Old Thumper. Any suggestions for a kit bitter to try that might fit the bill?