Ye'alright?

After living in this bloody country (as I like to call it) for a year and a half, I've assimilated nearly all of the slang and colloquialisms. I realised today, though, that there is still one expression that gives me trouble. It is common to greet people here with a "You alright?" (nearly always contracted as "ye'alright") as follows:

Limey A: Hello.
Limey B: Ye'alright?

What's not actually clear to me is whether Limey A should respond to the question or not. That is, should I say, "Yeah I'm good", or just keep walking? Aussies seem to have a similar thing with "How ya goin?" that doesn't necessarily require a response. In the USA, if you greet someone with a "how's it going?" you generally expect a "good, thanks" in return. This is what I usually do here, but I have a sneaking suspiscion that it strikes people as odd.

On a slightly related note, I've decided to practice my Brit accent, since it is still shamefully bad. We'll see how it goes.