Hi all looking for advice

My Astra has recently started having overheating problems, Its had a new Thermostat and the waterpump has been removed and checked and is functioning correctly but it still seems to overheat, It'll sit happily on 90 during idle but after 3-5 minutes of driving it'll overheat and creep upto the 110-130 mark and advise the engine has overheated and to idle the engine. I was wondering if anyone else has had an issue like this and what my next steps should be?