Just a quick update for the above. Item arrived this morning (09/01/16) so decided to do the job straight away. Removed the 2 x 8mm bolts underneath the glove box, pulled out the box, carefully removed the 2 x screws from the faulty resistor and then removed the connector (found this was easier than removing the connector first). Replaced the resistor for new one, put glove box back and then tested the controls 1, 2, 3, and 4.......................all work perfectly.
Once again, thanks for the info guys.