Best speakers for GaN1? Or should I change amps???

Focal speakers warm and rich? Doesn't fit any Focal speakers I have heard. I think Sonus Faber might be what you are looking for - the best you can afford used or new. Think Olympica Nova 111 or Serafino. There is nothing wrong with your amp but it is not in the same class as the speakers you are looking for. Speakers first then look for a high end amp to match the speakers.

OP - The Gan1 may not be best for you, but I wouldn't be so quick to dump it.  With your current speakers I don't think you can assume the problem is with the Gan1.  I've got a Gan1 and I've used it with Spendor S3/5R2 and Stirling LS3/6 speakers.  Both pairings sound great to me.  Do some research and select your new speakers - then see if they pair well with the Gan1.  If not, search again for the right amp.  Best of luck.

I'd forgotten about these amps!  I have analog and digital sources, so I never gave these any real consieration. 

I wouldn't worry about how they currently sound with your Ruark Epilogues, $300/pair speakers, but you'll need to decide if you can live with the input limitation.  Peachtree does make more "traditional" GAN amps with analog inputs.

I do think you've got it right - you're ready to get serious about your system and that means you need to get out and hear some gear.  For most of us, finding the right speakers is the crucial first step.  That'll determine what you need from your amplification.  Let us know when you have decided what pieces you upgrade in your system and have a budget.  Sounds like you're in the UK, so most of us aren't going to be much help with dealers, quality of in-country support, etc.  Good luck!

Haven’t experienced the GaN1, however, the GaN400 was one of the most disappointing amps I have owned among many. It had a loud noise floor for a SS amp and seemed much weaker than the specs alleged. I am not surprised they recommend high efficiency speakers for the GaN1. 
 

If you liked the Harbeth 40 sound, I recommend checking out the larger Graham Audio models like the LS5/8.