Was there actually an investiture ceremony? Alastair Bruce's
opinion on whether that was likely was "I fear that the normal way these things are done in that family is very informal. The box will probably be left open on a table and The Queen will say “there we are” and that’s that."
I don't think the service involved a formal installation in a stall like at the Garter service, simply because the stalls are not at St. George's Chapel, but at the comparatively tiny Savoy Chapel in London, which is much too small to host any major services. Catherine will have a stall there (I've seen a picture of Sophie's), but who knows if she'll ever get to use it.
Edit: I don't think Catherine was even at the service. The court circular says:
"The Queen, Sovereign of the Order, accompanied by The Princess Royal, Grand Master, was present this morning at a Service of the Royal Victorian Order held in St George’s Chapel, Windsor Castle.
The Duke of York, The Earl of Wessex, The Duke and Duchess of Gloucester, The Duke of Kent, Prince Michael of Kent, Princess Alexandra, the Hon Lady Ogilvy and Vice-Admiral Sir Tim Laurence were also present."
Likewise, Camilla wasn't at this one or the last one (which would have been the first after her appointment). She was, however, received privately by the Queen about a month after the appointment in 2012, and "invested...with the Insignia of a Dame Grand Cross of the Royal Victorian Order." I suspect that means given a box with the insignia in it, as Alastair Bruce describes. The same language was used for John Major's audience after he received the Garter, and it was filmed for a documentary. She gave him the accolade, then directed his attention to the open boxes on a table. Presumably he also received the more formal investiture with the mantle, etc. before the service in June, but I don't think that kind of tradition exists for any of the other orders (perhaps the Thistle).
