However I have been having serious issues with downloading apps off the Market since then. Whenever I try to do this I just get a 'Download was unsuccessful. Please try again' error message. I have tried to wipe the market, market updater and download manager cache but this does not fix the issue. I've also tried factory resets and that hasn't solved the issue either. The issue occurs on both Wifi and 3G. Strangely I can still install apps using the Market website (http://market.android.com).
I thought it may be an issue with the phone but after a factory reset I signed up to a new Google Account and I can download apps fine with that. However, I need to use my main Google Account as it has all of my contacts and app purchases on there.
Any help with sorting this out would be greatfully appreciated as it's becoming really frustrating for me.