how can i fix my 2002 rover 45 1.4?

hello i have a 2002 rover 45 that recently had a burst pipe replaced the pipe and the in car heater wont get hot but the temp guage says the engine is at normal temp but can over heat if the heater in car isnt running evan though it only blows cold air and recently it has started to just cut out when slowing down to stop at lights junctions etc it will restart but can be a pain to start sometimes can anyone help?