As a data point, it took us 5 days to get our bags. We had them re-routed from DUB to AMS and then picked them up at the airport once we received an email from the handlers here. Sadly that process took 2 hours but that's a whole different matter.

Despite us being home, we still needed to buy a couple of things as we needed a few items that were in our checked bags but don't have extras of. Can anyone offer advice on how best to claim those purchases back on BA's site? When I go through all the options there's nothing clearly for claiming items due to delayed baggage. All the processes seem to be about making a new claim or damage to luggage.