I have a Hangar9 P51 kit that I think they still make - it is basically a "trainer" P51 - it is called "Amazin' Grace". It came with wing attachments that you were supposed to use to help with lift, but I never used them, it flies so well. Hangar9, IMO, makes just about THE best kits and the manuals are terrific. I buy most of my stuff through horizonhobby.com or at my local Birmingham hobby shop - their pricing is exactly the same as HHobby's website. I've purchased 4 of their kits - the P51 I bought locally, then I purchased 2 Hangar9 "Pulse" kits, and a P47 kit that I have yet to build, but have gone through the parts kit. I have never even had a bent, broken or missing piece and never a question with the manual. I know that sounds impossible, but I consider them high end kits - each was in the $200-$275 range ($219 for Pulse). They are ARF, so you still have to put some things together, but I am a sloppy builder and can't paint or apply MonoKote, so the plane comes out looking great because ALL of that is already done me.
They may not make a ".40 size" P51 anymore - I know they have the blue and silver "Miss America" (mine was labeled "Amazin' Grace") and I think they have a new one out or coming out but those are ".60 size" - sorry, I'm in the US and can't convert millimeters in my head.

My P51 has a 55-65" wingspan. I think that you can not go wrong with a Hangar9 kit. I have heard Nitroplanes are good kits but never bought one -yet.
I have also heard nothing but horrific customer service and poor quality issues about Banana Hobby. "Avoid like the plague" is a good phrase, as I understand it. I'm sorry you had to go through that - it's bad enough to lay out a lot of cash for your hobby without getting crap for a kit, and then have to suffer poor customer service.
Good luck on your search - I hope this helps.
Best,
RP