The caller said I had been shortlisted to win a gift card after entering an Internet competition. He knew my email address. When I asked who was running the competition he said he didn't know. Then he said a website "offerx.com" runs the competition and that I would receive an email if I win. I told him I would delete, unopened, any emails claiming I had won anything.
I called the number he had called from tonight and I got an answering machine stating I had called "Josh from Future assist" which looks to be a legit financial service.
I found the whole thing extremely dodgy.

I called back number (03) 8765 4614 reached voicemail of a guy named Josh from future assist.