Originally Posted by
NotHamSarnie
If she wants a shower and a nap she could try the Yotel in T4. It looks like SEA-LHR currently arrives at T3 so I'm not sure if she'll be able to use the Yotel but it's worth a shot with her Z BP. She can always pay for an hour or two of use. If she is more interested in relaxation than a shower/nap, I would recommend going to T5 to the Sofitel hotel and having afternoon tea in their roomy sofa area.
You indeed can access the Yotel even though you flew into T3. However it's a little bit of a trip to get from terminal to terminal at LHR.