Hi there,
I have dealt a lot with Christopher Ward and they are a great company to deal with and make some lovely dress watches. With a budget of £4500 you could take your pick of any CW. You like dress watches and chronographs? Well just so happens the most beautiful CW in my opinion is a manual wind single pusher chrono (a complication that you could add another zero onto the price for a lot of brands!):
Failing that I'd be going for a Rolex Datejust for something dressy at that price or a Jaeger LeCoultre Reverso