40k in London is a fairly typical starting salary now, for any field. For the finance field it's pretty low even. Not trying to be... shitty about it, but just stating the facts. However, outside of London it's a pretty good salary (and converted to HK$, it's a very good salary for someone with just 2 years experience!).
When I graduated (just a couple of years ago) in the digital design field, my starting salary was just a couple of grand off 40k. It increased the next year (then I came to HK and it decreased!). I had an extra years experience working in the same area before I went to uni, but that didn't make a massive difference. A friend of mine who was in computer science was earning closer to 50k for a tech firm, fresh out of uni.
I think now the standard fresh graduate salary in London is 30-35k. But you can knock 10k off that outside of London, and perhaps a little more the further you move away from the South East. Still, anything below 20k for a skilled graduate in a decent industry is bad.
I had a friend who was earning in the low teens around the coast, but... well, he was blatantly earning much less than he should have been. The only reason he kept with it was that he lived with his parents at the time and it was a fairly nice/relaxing place to live (but economically dead).
In the finance industry though, things are typically much higher. There are fairly unextraordinary bankers in London earning annual bonuses in excess of 500k.
But trying to bring this back on topic... whilst 40k in London is fairly average and almost the norm for skilled fresh graduates, the same amount in HK is very good for someone at the same level. After SARS fresh grads here were taking job offers with as little as hk$6-10k per month, and even now most local fresh grads (investment bankers excepted) are starting off on around $10-15k. You'd have absolutely no problems supporting a decent single lifestyle in HK on $50k per month. Heck, some graduate invest bankers in HK don't even earn that