Jazz Conservatoire best for Multi Instrumental ?

My daughter will be completing 7 years of study in Jazz Piano/Jazz Singing Jazz Violin at the Purcell, International School for young Musicians. We spoke to staff at the RAM and they allow only one instrument study. Some courses allow two, but ideally would prefer all three if possible. She would expect after graduating to perform all three and also combine Piano-Singing and Guitar-Singing, Classical songs for weddings & etc. If None in her home town, London, could include all three, she may need to drop one instrument study before completing her 7 years, (probably Violin), at Purcell. Also am thinking of her working at any performance Gigs she can get for a year, or maybe two before applying to a Conservatoire. Would that help or be detrimental in some way? Btw she has 5 more years before then, so hope the economy has bounced back by then.