I am a Commercial Chancery barrister, having gradually migrated from the King's Bench over many years. I was for a long time a member of a Magic Circle chambers. Now I am a member of a less shiny chambers, through personal choice.
Sir Geoffrey Vos, as Chancellor, more or less abolished the Chancery Division - it has more or less merged with the Commercial Court in all but name. I exaggerate, but only a bit.
Traditional Chancery work is a fairly small field, and tends to involve less Court work than Modern Chancery. There are still small, not very well known sets in Lincoln's Inn where people advise on trusts, wills, partnerships, and so on. Such sets may have few or even no Silks (they don't really need Silks), and may offer few pupillages. They will still, however, demand very shiny academic qualifications.
I agree with those above who have suggested that the thing to do is obtain a tenancy somewhere. Think strategically. You can build your own practice. Don't rely too much on clerks, unless you are in a top level set. Manage your own career, and learn how much you should be paid - don't be afraid of fee negotiations.
Move chambers when ready - you will need to make a business case to the set you seek to join.
Try a sideways route: Maybe spend two to three years working in Jersey, where you can do trusts, trusts, trusts. Maybe qualify as a Jersey Advocate (two years residence, quite tricky exams). Or do a year or three as an associate in a barrister-led litigation team in the BVI (high value Company disputes and huge fraud cases). Then come back to London with a very sellable CV, experience above your years, and a great contacts book.
NB: Jersey is a pleasant place to live, and it's thirty five minutes flight time from Gatwick: you can leave the Royal Courts on a Friday and be on time for an opera and/or dinner in London. Jersey has some of the best trusts work on the planet. The BVI are a tropical backwater that are at least a day's tedious journey from London and half a day from New York. No high culture, terrible food, good scuba diving, OK sailing. The BVI have some of the best company/commercial litigation on the planet.
A team can go from the lower leagues to the Premier League. A driver can go from the back of the grid to a drive at Mercedes or Ferrari. I know two very shiny Silks who started out in really quite bad chambers and are now in two of the best sets.
Good luck to your partner.