Frequent entries to the UK with a visitor visa, am I likely to be refused?

Need some advice, here is a brief overview of my situation:

-I am Canadian.

– I lived in London for two years on a Working Holiday Visa (2015-2017).

-I live in France with my partner for two years. My current visa expires on March 3rd, but I have a renewal appointment on March 29th.

-I intend to go to London and I would like to stay with my sister (she has a working holiday visa) until June (so for 4 months). Our plan is to work together to research and write a business plan for opening a bakery in London and applying for a business visa.

-I also plan to return to France frequently (every weekend or almost) over the next 4 months to spend time with my partner.

– I do not currently work, but I have 18,000 dollars in savings.

– I have never been refused entry to the UK and I would like to keep it well, in light of the imminent visa application.

Two questions:

-What is the reason I should address all these issues with border officials?

– Am I likely to run red flags / to be refused for subsequent entries if I arrive in the UK every week for 4 months?