Hello BarryandKurt. Bit tricky this one as you'll arrive in terminal 5 but depart from terminal 4. Arrivals and departures are kept separate in T5 so you wont be able to make use of any airside lounge facilities there. To the best of my knowledge that means the canbanas will not be available to you on this occation.

You can however use the arrivals lounge in T5 by going landside, and then check back in to T4 when the closes closes at 2pm.

Alternatively, just go straight to T4 as a transfer passenger - all of the facilities offered at the T5 arrivals lounge will be offered in the T4 departure lounge too, the only real difference is the decor.