In April I'm flying

LHR-DUB
DUB-LHR-LAS

I am due to arrive in Dublin at 11:45am and leave at 1pm and I have luggage, Flying CE both ways and First onto LAS, is this possible to do with luggage? I had originally intended to check my luggage first at LHR to Las and not take it to Dublin but have read a few times now that check in agents are refusing to do this?

Any thoughts would be welcome