LHR Connection - What is reasonable?

[RJ2002]

6 hours ago, Gilly said:

https://www.frankfurt-airport.com/en/flights-and-transfer/transferring-at-fra.html   is the best I could find.  We've been through FRA a couple of times in the last month and I'd say that on both occasions it was busier than LHR.   Most recently, we just transferred from one Lufthansa flight to another on our way home from Trieste and thought we'd have a couple of hours to enjoy a beer and restock the Gummibären but the transit between gates (involving passport control since we were leaving the EU Schengen area and flying to UK) took more than an hour and we headed straight for the gate, not wanting to risk it.  It was another one of those passport controls where the queue was very long and people with short connections were coming forward in the hope of making it in time. If you don't have to undergo passport check or change terminals, then I'd say it's simply a case of walking time.

and for Frankfurt, it can be a LOT of walking - depending on your arrival and departure gate 

[Gilly]

8 minutes ago, RJ2002 said:

Frankfurt, it can be a LOT of walking - depending on your arrival and departure gate 

Yes indeed!   If that's likely to be of concern, I'd arrange assistance without thinking twice.