I am related to this family through the Culvers and my understanding is that our best claim to UEL status is through Catherine Culver's grandfather Timothy Collver. I am not sure how you get the proof you need, but here is what I have from Robert Mutrie's Collver genealogy.
Catherine Culver was born at Townsend Township 30 Jul 1799, died 1893. She married John Learn. They farmed near Mapleton in Yarmouth Township.
Catherine's parents were Jabez Collver/Culver and Anna Collver. Jabez was born at Wantage, Sussex Co., New Jersey 22 Sep 1757 and died at New Sarum, Yarmouth Twp., Elgin County 9 Aug 1829 ae 71y 10m 18d. He married in New Jersey, Anna Collver (daughter of Timothy Collver), born at Schooley's Mountain, Roxbury Twp., Morris County, NJ 13 Feb 1765, died at New Sarum, Yarmouth Twp., Elgin Co. 5 Apr 1847 ae 82y 1m 20d. They are buried in Mapleton Cemetery, South Dorchester Twp., Elgin Co.
Timothy Collver has already been recognized as a United Empire Loyalists and has been well documented by the Grand River Branch. You should have no trouble being accepted on the basis of being one of his descendants.