Hi Andy
I'm afraid this is typical of Wickes attitude towards their customers and the main reason I will never buy from them again, having had a similar experience to yours in the not too distant past. I did however stand my ground and on that occasion won the day and left with a refund, however it was one hell of an argument and not one I'm in any hurry to repeat. Say what you will about B&Q but they have always refunded or replaced at my discretion on any tool I have had to return. They even recently replaced a 9" angle grinder with a better model for the same price and because the fault was a broken spindle lock gave me a new diamond blade to replace the one that now couldn't be removed from the faulty item.
The most important thing to remember is that the sale contract is between you and the retailer not the manufacturer, all goods sold in this country must be of satisfactory quality and fit for the purpose for which they are designed. The other important change to this legislation is that since January this year the onus has been put upon the retailer to prove that a returned item is satisfactory and it is not encumbent upon you to prove that it is not. Another important change is to the length of time you can return an item in, previously it was generally accepted that a retailers liability stopped at twelve months, this is not the case you can now argue that an item depending on its price and or quality should last longer than twelve months. My father recently returned and had replaced a Sony that was nearly three years old arguing that it is not unreasonable to expect a quality item such as that to last longer than three years, in this instance the retailer in question replaced the item with no fuss, thus retaining a customer and also gaining one (me) due to their good attitude.
I truly hope you manage to get this situation sorted to your satisfaction but either way I think the moral of this story is that we should all think before we part with our hard earned and if a few more pounds buys us better service then stick with the retailers who look after us. I have found one or two that I trust and now try to put my business their way.
Best of luck
Richard