PhD with Master's but without Bachelors

I left University early (during the final year) and was only awarded an associates degree (one level below a full bachelors) in Computer Science.

I've been an IT professional for a few years now (development and consulting) and I'm looking to fix my broken educational record.

At this point, I could enter a bachelors programme in the final year and upgrade my associates degree to a full bachelors OR I can go straight into a Master's degree. Several Universities have offered me entry to their part time Master's degree in computing off the back of my associates degree and work experience.

I'm at a loss as to what I should do?

I've always wanted to do a PhD in software engineering project methods or maybe something more comp sci based but I fear that a masters without a bachelors won't be good enough to be accepted anywhere.

What do you think?

Thanks