Robinsons do one I think. Libbys do a synthetic one. It depends on the sort of quality you are looking for really. My YO is getting a new one but she is going to a local market to buy hers.
I have a rene schoop set- like the zilco but cheaper... I paid £550 for mine but the zilco equivalent is £850. Depends what she is doing- for pleasure driving, something like libby's or pals equestrian is fine- the imported leather sets are ok as long as you look after them, I wouldn't pay more than a couple of hundred. Or less than £100 secondhand!! You get what you pay for and for me safety is paramount especially when you're sat behind it rather than on top! I chose my set as I'm doing HDT at pre novice level and need a set that will stand up to marathon and be smart enough for dressage- here's mine...
I have my Indian Leather one that cost me £85 on ebay and then my OHs Harness cost him £1200 (english leather) and then a ploughing harness costing something in between.
If she wants synthetic I highly recomment Zilco or Top Mark. And if you want my opinion Libbys ones are rubbish, and I wouldnt even touch the Robinsons one.
Howeever I see no problem with a fair quality indian one.