
I have brewed this beer many times with both Lyle's golden syrup and with CSR golden syrup. The CSR is in a larger container and is darker in colour (I just use the whole container either way) so there would be, but I've never measured the difference, some small change in the finished colour and gravity of the beer albeit marginal. For my palate, I can't taste any difference.
I haven't tried different yeasts, I just use the Danstar Nottingham. It does need to rest for a week after the initial 'active' ferment to allow the flavours to mellow. I do prefer my beers to be dry rather than sweet. I've had my best results fermenting at 12°C. That's the beauty of Danstar Nottingham, it works well at Ale temperatures, but even better at Lager temperatures. I've been able to get this yeast to kick off at 8° and then allowing it to rise to 14°, it was a 3 week ferment but I have the patience. It's a very versatile yeast.
So to conclude, I would advise varying the recipe by varying the fermenting temperatures to find what has the best results for you, before changing the recipe's ingredients.
Cheers
Hashie