See standing rules 42 through 46 but in particular 44 (2) which reads
If any Member be suspended under paragraph (1) of this order, his suspension on the first occasion shall continue for five sitting days, and on the second occasion for twenty sitting days, including in either case the day on which he was suspended, but, on any subsequent occasion, until the House shall resolve that the suspension of such Member do terminate.
I believe this can only be done in response to a motion and vote. The authority to unilaterally order a member to withdraw is only for one day see 43. So you are correct.
https://www.parliament.uk/business/publications/commons/stan...