Getting a tire off the rim - 37-622 Ive tried everything and can’t seem to get the tire off the rim. I’ve double checked the bead and it’s loose. I pushed the beads into the centre.  I’ve tried warming up the tire. It almost seems the tire is smaller than the rim. I try and use the tire leaver to lift it but it almost seems to grab both beads at the same time. I can’t lift one bead up over the rim edge. I really don’t want to take it into a shop as I’ve changed other tires quite easily. I also tried the front tire Incase it was just an issue with the rear one I was working on. Natta. Any suggestions?

Soap and a bunch of muscle power did the trick. Thanks so much everyone.
Counterintuitively, one pump of air in the tube may help separate the two beads of the tyre, allowing you to grab just one with the tip of your tyre lever.
I have a bunch of tyre levers, and some are good while others are dreadful.    See if you have one with a flattish front, not a spoon or bill shape.
It can help to use some cable ties or velcro straps to squash the tyre into the rim's internal valley.  Then work your way around the tyre pushing the whole thing into the rim whilst moving the excess around the circumference to the opposite side.  This is generally how one would fit a new tight tyre like a Marathon.  You're doing the same process in the same order but aiming to get the bead off.
Last resort, if the tyre's dead you can cut it off but this means the tyre can't be reused,