Why is my flow fluctuating so much?

[Ambaz79]

Turns out my son was going for a shower for over 20 minutes after school. This was emptying the tank. I've kept the Circulating Pump off and might just remove it. I've set the tank to warn once at night and once in the day. Also restricted my sons shower to less than 10 minutes. Not sure this is being fully followed though! We are getting through 24 hours with just 2 cylinder head ups. Thanks for all your help on this. 

[Dillsue]

If you want to retain the HW circulating pump you could fit PIR movement sensors in the bathrooms and use those to start the pump as soon as someone walks in but definitely need to insulate the flow and return. You also want to get all that pipework around the cylinder insulated particularly all the tappings other than cold feed. For the tappings you want the thicker walled insulation butted right up to the cylinder casing and ideally shaped so its in contact with the insulation inside the casing. If any or all of your tappings are warm, youre losing heat 24/7!!