It's probably not possible to get the exact same agent to call back to you , and yes some will promise to call back, and don't.
However, there's more likelihood of reaching a Dublin agent if you contact Customer Services first thing in the morning when the lines first open at 8 a.m.
This is the easiest and quickest way to contact eBay Customer Services, for a Call Back option.
https://www.ebay.co.uk/help/eua?id=5275&mkevt=1&mkpid
Lines open 8 a.m. - 10 p.m. on weekdays
9 a.m. - 6 p.m. on weekends.
Automated agents will be available on chat outside of the above hours.
@thetooloutpost