Many clients won't trust their bank info to third parties
I'm missing something here. By "clients" do you mean buyers? Nothing has changed for buyers, except that they pay eBay, not the seller. They don't have to provide bank details. They can pay by PayPal or any of the other methods accepted at checkout.
By the way, the fact that you're terming yourself DPLtrading, with about 1200 items for sale rather suggests that you're an unregistered business seller. It may be this, plus the fact that you don't accept returns, which business sellers are required to do, that's putting buyers off. I think you need to decide whether you're a business or a hobbyist. EBay is now assisting HMRC to identify unregistered business sellers.
