The car is perfect when starting from cold, but driving it for about half an hour and turning car off and go to a shop for 10-20 mins and try start the car it will just turn over but will not fire up. I heard it could be crank sensor?
Also my engine coolant bottle uses alot of water, any reasons why? But my main issue is the hot starting issue.
Possibly could be the crank sensor, or TDC sensor as they're known, it may be worth cleaning the connector up a bit first, to see if it makes any improvement, I think there's a guide on here of how to do it. My old clio had a similar issue with the starter motor, after the first start it would turn over fine, but I found the starter motor wasn't throwing the pinion gear out fully to spin the flywheel, took the starter motor off, stripped it down, greased, and all was fine.
As to the water usage, on that engine, the thermostat housings are very common to leak, they're located just under the air filter box, ideally if you look underneath the engine when it'r running, you will see the coolant drip down the NS driveshaft, and onto the sump. Thats the first place I'd look, but could be water pump related, head gasket etc, but if its running fine, I wouldn't expect anything too major. I think a genuine thermostat housing (comes with a new stat) is around £30 from Renault, always worth going genuine on something like that
