WFH 4 years, company now wants me in (4 hour commute)

I’ve been with the same company 4 years, I’ve performed and it’s on record. I was hired on a remote contract with occasional travel to the office.

I have ADHD so this works really well for me. Anyways all new hire are 3 days a week in, and now it’s only me fully remote.

They’re talking about me coming down frequently. How frequently are they legally allowed to ask for given I am 4 hours away + my contract says ‘occasional for meetings’.

Really looking for a definition of occasional.