Firstly, It may be worth having the set up looked at or changing the strings on the violin she has as it is possible to make immense improvements to a violin that way. Can I ask what is wrong with that one ?
I have been to well known violin shops and played instruments into several 10s of £1000s & I can say that the value genuinely does not necessarily correlate with the tone. Sadly you are dealing with a market somewhat akin to the art market where prices are artificially high - it's an investment market. There are Picassos I'd love to own, but I may not necessarily like them.
Now, if you have the money to spend on a violin that sounds nice, has a genuine known and respected label and is also worth tens or hundreds of thousand pounds or ( a lot ) more, you are lucky, as this instrument will certainly appreciate in value. In fact over time just about any half decent instrument will appreciate in value, but the now ridiculous prices are very much governed by that investment market, which is why the moment interest rates are low, the price of things such as paintings, violins, and bows goes up.
There are people who own violins worth hundreds of £1000s who prefer the sound of an 'inferior' instrument they own. It's very much a personal preference. If your daughter has no intention of becoming a musician ( a decision which TBH this year would seem to be eminently sensible ) then you have a couple of things to consider - the tone and the carrying power and if possible something that also looks quite nice.
Just about the first question you get asked when you walk into a luthiers shop and say you are looking for a violin is 'what is your budget' Somewhat suspiciously, most violins are also not labelled with a price but an 'antiques dealer' code....
I have played as Minstrel would call it, a 'starter run-about' modern English violin for most of my violin playing and teaching career. It not only looks nice but it can knock spots off many other violins I have played, some worth many thousands of pounds. I have played Bruch, Beethoven, Mendelssohn, Mozart, Bach concertos and the 4 Seasons on this violin as well as numerous other violin solos of the symphonic repertoire on it. It was a lucky find, a warm powerful even tone that can compete with an orchestra. I have other violins worth more money, but this is the best - as well as a small collection of various instruments I have bought on spec, some of which are cheap but good quality Chinese and cost just a very few hundred and are really superb. So, she needs to play lots of violins, borrow them, show her teacher, get her teacher to play them so she can hear what they sound like externally. If I can say one thing, do not accept you need to spend x amount of money. Violins are not like cars at all.
As Minstrel says, a good bow is very important, more than that, it is vital. Again, do not discount more modern bows as 'inferior', she doesn't need a Peccatte.