Wharfedale Jade 3 aluminium tweeter problem

There may be more break in needed with an aluminum tweeter and overall most speakers continue to mature and evolve over the first year or so.
If your using class D power this kind of sound is not that unusual. An expensive approach albeit hard to swallow is to seriously think about a class A power. That isn't cheap but there are some amps that have a bias that produces mainly class A. An even more wild switch and I hope not annoying is to use tube power amps. You may find your audio nirvana that way -honestly it made me stop thinking about any other amps. (well I could be tempted to try some others but...)
Finally if you don't mind using cables as tone controls and I think it is perfectly fine to do so, get warm cables made of copper. I think Cardas has been the best, but the older "golden" this or that were the best at providing full rich sound, don't know the current stuff. I also like Jena labs cables but she's expensive, so I bought used.
Good luck but if you really hate them, just take them back and get the best deal you can for a better speaker for you.

Wharfedale Jade 3 aluminium tweeter problem
Breakin is a combination of several factors. The easiest notion to comprehend is loosening up the surround and the many important elements of the suspension. If wood is a major player the cabinet it contuse to dry or absorb or dissipate the atmospheric humidity . Paper cones I would think The crossover matures or burns in as any piece of good electronic piece of gear does. The magnetic elements loose some of their strength (not obviously until much older) our ears pick up all these perhaps small changes in aggregate and the burn now seems obvious and it continues throughout the life of the speakers,.
I know I have ny Father old JBLs approx. 57 years old which need to be refreshed.
Don't forget the changes you would get using a modern tube power amp. A tube anywhere in the path does not make the system tube in all that discussion..
by Mechans

No not really, I have aluminum inverted tweeters on my Focal Electras and the tweeter was mercilessly and revealed everything in the system. I got some tube power amps and Holy Moly these tweeters found the right amplification and I don't mean rolled syrupy slow sound you remember from your grand parent's RCA console. No they quick crystalline and create a huge soundstage. Imaging that you can easily call holographic.
When I had friends over to listem I wouldn't say much about these relatively inexpensive tube monoblocs. Every comment that my speakers sounded a lot better, what did I do to get them to sound better. You know the punchline.
As for your tweeters they do break in hard or not it is suspended and has electronic elements and magnet in them. You are right they don't get burned in as fast as the other elements. Only time and listening will let you know if all the drivers in your speakers are maturing into a cohesive unit where they mesh well. The tweeter is a part of it but not the only one.. That said if you keeping your equipment as it is today you may be ready for a nice silk or whateve fabric tweeter. Do you any audio buddies around, if you do you can ry your aluminum tweeter with various amplification.
If you just can't stand them return them and get a fabric or paper tweeters. The time and discomfort with metal may not be worth it to you and I don't blame you. In another life I hade two systems The one with the Focals and many amps and sources, but wasn't until I found the right amps with the help of Trelja on these forums after 6+ years of trial and error (mostly error) I found nirvana.
The 2nd living room system is and was easy to listen to. Von Scheickert VR 2s powered by a smallish el-34 integrated. I had a MMF-5 turntable there and a couple of tuners one an old Sherwood and a Sansui the first cd player was a Music Hall MM CD-25 player.
I wish you luck be forewarned this hobby is addictive in some people.

Cables cost something. potentially a great deal, unless he promised them for free.
My guess is that you might need to change more than cables to achieve the sound you want . I would hear him out with the cable cure, but then it is time to change the speakers.