Am i checking the cooling fan correctly

Thanks again for the replies,one thing i just dont understand ,when the car is running on normal load the temp bars go up to two bars it takes standing traffic for it to reach 3 bars ,also on the motorway it will stick at 2 bars for hours , it will only hit 3 bars when i go up a long incline but even then it will drop back down to 2 bars ,if the thermostat is sticking open how will that stop the fan kicking in by not getting to temp because when i am stuck in traffic it gets hot stays at 3 bars then jumps up to max and red surely it must hit the temp for the computer to kick in at some point if that makes sense

Another update,i have replaced the thermostat today and refilled the coolant, I travelled the 6 miles to home were the bars went to 3 and stayed their ,however after 5 miles the temp went to max and beeped ,then after a few hundred yards it went back to normal, when I got home I left the engine running opened the bonnet to see it needed more coolant and while topping up I noticed the fan moving albeit for a few secs ,it started again for a few secs then stopped, I have done a further 20/30 miles today with all bars staying on 3 I have opened the bonnet on several occasions to try and see if the fan is kicking in but as to date I have not noticed it ,maybe its just not getting hot enough

Another update, I travelled my usual 7 miles home this morning ,temp showed 3 bars after a few miles and stayed until I got home ,I put a mark on the fan and the shroud ,took the dog for a 15 min walk and left the engine running ,when I got back I noticed the fan was not lined up with the mark I put on the shroud,i presumed it must have kicked in,i decided to stay and watch and eventually the fan kicked in but when I looked at the temp It didn't to kick in until it hit the red , it then cooled it back down to three,i suppose I now know the fan is working but I thought it would have kicked in before it hit the red max .