my shortlist for integrated Harbethsuper hl5 plus xd - please advise

FYI on the Luxman L509x. It is at the end of its production life and will be replaced with a more costly L509z. You may start seeing more 509x models on the market. I have the current L505uXII. I am very pleased with it, but sometimes I wonder if the higher models will give me “more” of what the L505 does.  All in all I am thrilled with the “entry level” Luxman integrated. Good luck in your search.

of your choices i would go exposure

but better yet i would buy a hegel integrated within your budget which i believe will sound better than all of your slate 

You should check out LFD ( solid state ). Give GR a call as he is a big Harbeth dealer! BTW, I own those speakers and I use tube amplification!

https://generubinaudio.com/shop/ols/categories/amplifiers

Moonriver 404 or 404 Reference, I was told they were being developed using BBC family of speakers all though not exclusively so, are said to sound great with Graham Audio speakers.

I would also seek out a VTL IT-85. A magical amp with many Harbeth. At 70 wpc It has the power that an HL5 needs. Also as important it has a more neutral (for tubes) tonality which the Harbeth's also need.