Spouse visa advice

[JCK]

I am looking for some advice regarding a spouse visa that we will be applying for shortly.

To cut a long story short, I met my Sri Lanka partner in the U.K and has been together for 6 years. Due to them overstaying for a year, they had to leave the U.K this year. They left voluntarily and paid own flight.

We are still a couple and in contact everyday. My question is, following advice from my solicitor, this overstay will not have no impact on a spouse visa. Is that true or are we just wasting our time and money applying?

Secondly, on the gov uk website, it states that if you are a proposed civil partner, we have to prove that we will enter into a civil partnership. But how is that possible? I have been in contact with the registry office and they advised me that they cannot make any arrangements until my partner is here in the U.K with me.

Thanks in advance for any advice