I've used both- you'd want a Twin room at Yotel so you've got space and they only have two. Bloc maybe cheaper but you'll need one of their larger rooms.

Any other option the walking/check in will eat in to your layover time

Do not hesitate any further to book this - a couple of horizontal hours and a long hot shower will really make you feel better !

Just checking as well that you've booked a transfer - I use BA Transfer as a very cost effective option and I believe they have car seat if you need it. Others are available- e.g. Addison Lee and Blacklane are more expensive but reputable