If bought at B&Q were they in the outdoor nursery section?
If so they would have been hardened off ready for planting outdoors. If you bring them indoors they will react badly to central heating and shortage of light!
You will also have to harden them off again before planting outdoors. A cold frame or cold greenhouse would be needed for hardening off. Parsley is a Biennial and Thyme is a perennial so once established they should be able to cope with outdoor conditions.
The 'pot herbs' you buy in supermarkets will thrive on a windowsill though!
