Buying NI Reg Car

Hi,

Does anyone have any experience of bringing a Northern Irish car into England? I know the Gov.uk website says that vehicles can be moved freely between Great Britain and Northern Ireland, but would I have to re-register the car or anything? Also, would the car insurance or tax be higher? We are moving from the Republic of Ireland, and have heard that it is a major hassle to being an Irish car over and register it etc. So we are trying to decide whether to drive up North, buy a car and drive it over, or buy one in the UK.

Thanks a million