UK Visitor Visa return Question

[jmack47]

I arrived in the UK June 1st on a 6 Month Visa as I took a career change in an agricultural field and continued to pursue my relationship with my UK partner who I met in Australia. I left for Canada Sept 1st: spending 3 months of the 6. Can I return to the UK mid December for 2 months on the same Visa before proving I have the financial resources, exit flight to Australia (where I am a perm resident and will have work waiting) Or do i need to apply and thus pay for a new visa in advance, as the 6 month period will have passed.

Also:

-I did not receive an exit stamp
-I have no intention to reside in the UK apart from the timing between the polar harvest seasons and no intention to work: my partner will provide my housing means.
-We do not qualify for de-facto status.
-There would be a liklihood of returning June-Sept again: if it is worth getting a 1 year Visa

Any help answering the question is appreciated!!