Hello KZOOM

I am afraid that the T1 (domestic or international)-T4 transfer is a nightmare for luggage. (and sometimes also the T1 domestic-T1 international transfer is just as bad).

My experience is that even travelling F and J, the bags just do not make it across, with transfer windows of between 90-180 mins. This was the case on my last four trips. They must really try hard to be as bad as they are with this transfer. They are not even very good at putting your bags on the next flight to your final destination.

If I have the time in future, I will pick up my bags and check in again at the other terminal if I really want to travel with my bags. If not, I'll be packing a change of clothes in the hand luggage.

And yes, Heathrow Express is free in standard class between T4 and the other terminals.