What should you do? #1 do not get on an airplane for a long flight. If you absolute must fly to England then make sure you get up often and walk around. It is well documented that sitting for long periods on flights increases the risks of clotting even if one is not in Afib. Wear compression hose to improve blood flow from your legs. #2. Do not listen to people here telling you what drugs to take. Some of these drugs come with significant side effects. Some are meant to reduce your heart rate. Your HR may not be high enough to take these drugs. Some are also used to reduce BP but you do state what your BP is. No one here is qualified to suggest taking drugs just because they or someone they love takes drugs. I only take Eliquis for Afib. I do not need any other drugs. But that is just me and just because I do not need additional drugs doesn't mean I should tell you that you do not need further intervention.
Take Afib seriously as it can cause a clot and or kill you. CDC says" In 2019, AFib was mentioned on 183,321 death certificates and was the underlying cause of death in 26,535 of those deaths."
https://www.cdc.gov/heartdisease/atrial_fibrillation.htm
That is deaths only. Strokes caused by brain clots debilitate thousands every year. So do not listen to those who say Afib does not kill.
From the same article I linked above. "AFib increases a person’s risk for stroke. When standard stroke risk factors were accounted for, AFib was associated with an approximately fivefold increased risk of ischemic stroke. AFib causes about 1 in 7 strokes.
Strokes caused by complications from AFib tend to be more severe than strokes with other underlying causes. Strokes happen when blood flow to the brain is blocked by a blood clot or by fatty deposits called plaque in the blood vessel lining."
2 months is a long time for a newly diagnosed person to wait to find out how involved your Afib is. Do you have other options at least to see if you need an anti-clotting agent to protect you until you see a Mayo doc? For years I managed intermittent Afib with only taking Eliquis during and shortly after I had an event. But I always knew when I was out of rhythm. You state you do not know how bad your Afib is. Think again how important this trip to England is for you. Do you really need to fly long distances and be out of country for that long a period?