SainT, first of all, great that you consider electrical equipment waste to be also your concern. Although Jag GD is most likely never going to end up in a bin, this approach is commendable. I do not remember seeing anything related to recycling in any of my modern retro purchases, as you implied.
Technically if you're compliant with UK EEE and WEEE guidance, it means you should be compliant with EU too. UK is still in EU and the whole point of the union is that member states are aligned in matters like this. If you now decide to prioritise UK and non-EU customers above EU customers, you should clearly communicate that to everyone who has made the pre-order. Having distributors is also a good idea, but will not automatically sort out the pre-orders.
I understand you're doing this as a business and shortcuts won't be an option. Maybe this company can help: https://erp-recycling.org/uk/