Normal
I would speak to the firm to see if it possible to get the first week contracted at 20 hours and only attend 20 hours (just under 3 days) on that first week (eg miss the Friday and leave slightly early one other day that week).The firm doesn’t need to rescind the offer though - if it is the case the can’t accommodate 20 hours in the first week, then you cannot meet the terms of the offer, so they don’t have to rescind because the you cant meet the employment contract’s terms.
I would speak to the firm to see if it possible to get the first week contracted at 20 hours and only attend 20 hours (just under 3 days) on that first week (eg miss the Friday and leave slightly early one other day that week).
The firm doesn’t need to rescind the offer though - if it is the case the can’t accommodate 20 hours in the first week, then you cannot meet the terms of the offer, so they don’t have to rescind because the you cant meet the employment contract’s terms.