It is, in my opinion. I avoid eating the roll or 'Full British' on flights into LHR and ask for something light (fruit or similar) and coffee/juice, land, make my way to Arrivals and eat there, work on the laptop a little, then refresh, leave.

The breakfast in Arrivals is much more substantial, help yourself, and you can have a bigger plate if you feel so inclined. As I work for myself, I'm not in any huge pressure to leave either.

I'm not sure if anyone else does this, but as I always park in LHR short term, I've been known to choose level 1, drop my bag off in my car, then go back into T5 and the Arrivals room! Adds about 10 minutes, but you don't need to worry about dragging your bag.