Private dental treatment from NHS Dentist -advice please

bluenose1

Went to the dentist today as a piece of tooth fell off  one of my molars. I am 54 and most of my back teeth have fillings due to a sweet tooth over the years. The dentist advised he could do a crown on the NHS so I am really pleased about that as thought he would just have to remove it.
My two front teeth and one next to it are crowns I had put in when I was 18. All 3 teeth are pretty much same size so actually looks like I have three front teeth, I showed my husband when I came home and he had never noticed before!!! My teeth are also too crowded and yellowing. I have never been happy with them. 

The dentist mentioned all this to me and said he could replace all the crowns, veneer at least one of my teeth, whiten them all and said something about  braces.  He then showed me pictures of before and after of patients and wow the difference was amazing.
The cost would be £5,000 which to me in the grand scheme of things actually seems quite reasonable, considering work involved etc. Though I worry if cost may go up. 

I suppose I am just worried about spending all that money after a 10 minute chat and if I should shop around.  Or are there other things I need to consider?
Any  thoughts much appreciated.