Is my room big enough for the Harbeth HL5's?

You may want to post over on the Harbeth forum. Many users there and plenty with smaller rooms as they are largely from Europe or Asia.

When you listened to the SHL5 at Fidelis did you do a direct comparison to the 7es3? I ask because as you say you fell in love with the SHL5, but what you need to keep in mind is that you fell in love with them at Fidelis, in their room, with their gear.. Being as the 7es3 has the newer Radial 3 woofer and is a newer design if it was my coin I'd want to hear them head to head before I made the switch. At least you'd then know what it is you prefer about the SHL5 over the 7es3, or if it's their setup. And FWIW I don't think your room size is an issue at all. I used mine in a room 15' x19 and I never felt like the room was the problem.

I don't want to take this thread too far off topic but can someone explain to me how a smallish, table top sized speaker like the harbeth can be considered too big for any average size room like the one used by the OP?

Please don't take this as being disrespectful as that is not my intent here. I am someone who has full sized tower speakers with multiple 10" drivers per cabinet in a room slightly smaller then the OP room so I am having a hard time wrapping my head around a small speaker like this ever being considered too big.

Thanks

By my reading nobody has said that the OP's room is too small for either speaker.

The 5's should work fine in your room, but listen to both in your room if possible. I listened to both in the same room, same components and music and determined which one I liked better for the type of music I listen to. Newer doesn't mean better. Some folks prefer the 7 and others the 5. No right or wrong answer here.