Upvote:2
How much additional time will baggage reclaim take, given that we have to go through immigration (USA passports) anyway? Will the bags likely be waiting once we clear the passport examination?
Passport queues for non-EEA residents can vary from one or two minutes to over an hour. It is not easy to give an estimate, especially as you do not mention what time you are arriving. Bags should all be delivered within thirty minutes although delays are hardly uncommon.
If you are connecting to an international flight (excluding to Ireland and to the Channel Islands), you have your onward boarding pass, and you have hand baggage only, you can use the Flight Connections channel to bypass immigration, bag claim, and customs. You will go through security and into the departures hall. If you can I would advise against checking your bag.
If you do have to pick up your bags you can use the Gatwick Connects service to recheck your luggage back in and collect your boarding pass directly, it's in the luggage hall. This may save you a few minutes.