Hi there, thanks for the background info!
So my impression is that doing a period of just side-swaps would help, since you mentioned you just swapped them for the first time recently. Usually I like to do side swaps for at least a week or two before doing full-on bonding sessions. I think maybe a brief pause with just side swaps could lower the temperature a bit, especially given the fight they got in. Sometimes I’ve found that mounting really calms down after this “pre-bonding” period because they get really used to each other’s smells. And yes definitely make sure those walls are tall, and with a buffer to prevent nose nipping. You can clip a sheet to the top of the pen as a roof as an added precaution.
My other suggestion is to try a larger space. I’ve always had better luck with larger spaces than smaller, so I usually try to use an area that’s at least 1 x-pen, ideally 2 x-pens linked up. The rational is that when sessions start getting longer, sometimes they want to move away from each other (which is part of communication). If the space is too small, they have no where to go and it can lead to things escalating to fights that otherwise wouldn’t.
Also make sure your space is really neutral, sometimes even being with smelling-range of their home turf can make things more challenging.
Overall though I don’t think it’s going too badly! I think with some side-swaps and a larger space you will see some progress.
When he goes to mount and it looks like she’s going to turn and fight him, prevent him from mounting and pet them both to calm them. Same when she requests grooms, pet them both and swap scents. You will eventually ease off this much intervention but for now (since things are escalating to fighting) you want to focus on getting them calm around each other again.
.
.
.
The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.