Information and Inspection Powers: Inspection Powers: Co- operation at an inspection
The occupier has the right to refuse you entry to the premises. CH25650 explains what to do in such a case.
If you are on an inspection of premises and the occupier decides not to continue with the visit then you should withdraw immediately. You should offer another time to complete your work or remove the records presented for inspection, see CH23300, and continue inspection of them on HMRC premises.
If the visit needs to be cut short due to external factors on either side, withdraw politely after making arrangements to continue your work on another day.