Upvote:2
As stated by Timatic, the database used by Airlines:
Passengers may make a landside transit if holding a valid biometric visa issued by Ireland (Rep.) endorsed "BC" or "BC BIVS" and traveling to Ireland (Rep.).
The GOV.UK Website confirms the same:
You might be eligible for ‘transit without visa’ if [...] [having] an Irish biometric visa (marked ‘BC’ or ‘BC BIVS’ in the ‘Remarks’ section) and an onward flight ticket to the Republic of Ireland
Now, while both sources only state this applies when going to Ireland, the reverse is effectively true as well. The reason being, you do not clear UK immigration when arriving from Ireland, so you just walk to the baggage claim, collect the baggage and clear security.