Depends also on the company. If you did this in an advertising agency you may get more than if you do it for the local council. You could also be a PA with those skills, which also pays more... But on average I would say �12-15k a year..
Minimum wage for a 21+ year old is �4.85 per hour so 42.5x52 equals a minimum of �10718.50 per annum.
You should do much better than that, even at 20 years.