The amp is powerful enough and has low distortion figures so I don't think that changing it will bring much benefit.
Imho Class D amplifiers definitively have a 'sonic foot print' regardless if the figures read similarly to different topologies.
I am talking about the well known, well developed brands/products ie. Hypex, Pascal, ICE.
My previous active speakers used these.
Cheaper chip amps such as the OP's will likely follow a similar sound signature , albeit likely less refined.
The sound I am talking about is a lot of grip and punch in the bass but in a somewhat dry fashion. Good detail retrieval but lacking a little cohesiveness ... the thing that knits everything together and by far the biggest trait standing out ... dry'ish upper mids and treble.
Now I don't want to overstate this. The above is just my clumsy way of trying to put that 'footprint' into some words that perhaps make some sense.
In reality/use this may be a sonic signature some like and it's more subtle than my (clumsy) attempt to describe it but in direct comparison with good class A/B/G amplifiers it is easy to hear.
I think Class D, at least with non linear power (Switching) supplies, regardless of 'paper spec' have not yet evolved to a degree in which I could happily use them.
Having said all this, I have not heard every Class D ampifier out there but I have seen enough reviews and views about even the best measuring examples of today (Eigentakt/Purify) to gather it may not be all that it is supposed to be.
Words like 'control, detail, dark background, firm bass, crystal clear treble etc ' point to a product that you can admire from a technical point of view, one that can impress on first (even 20th) listen but may be a little harder to actually love listening to and keep for the long run.
Subjective stuff which the measurement guys will object to but my experience nevertheless.
So imho ... yes I would try some £1000 alternatives if I was the OP with the caveat that the speakers used may or may not reveal enough difference to make such an expense worthwhile.
I am not the biggest Bowers & Wilkins fan/follower so am probably the wrong person to advise on that even though my last (active) speaker I bought (and sold) was B&W's Formation Duo's.