Ann: Quarterly Activities/Appendix 4C Cash Flow Report, page-134

Why so worried?
I'm not sure they actually need REACH registration.
Even if they do, I'm sure ADO is on the cases if it is required. It's not that different from producing SDS documents for shipping and storage of any of their products.

Also, the volume needs to exceed 1 tonne pa, and I would doubt that ADO has passed this threshold yet.

Reading the below paragraph, it appears the onus will be on ADO customers to register the chemicals they import.

"If you are a company established outside the EU, you are not bound by the obligations of REACH, even if you export their products into the customs territory of the European Union. The responsibility for fulfilling the requirements of REACH, such as registration lies with the importers established in the European Union, or with the only representative of a non-EU manufacturer established in the European Union."

Understanding REACH - ECHA (europa.eu)