I have a Megaflo DD 210 litre cylinder (around 10 years old) and the top immersion heater is leaking. The immersion heater is not connected so I want to remove it and replace with a blanking plug. Has anyone got one available? It is 1 3/4" BSP which is larger than normal cylinder blanking plugs.

where is it leaking?
if its the thread remove and refit with ptfe tape
if its the element / thermostat ,remove plug the small holes they leave and refit

I originally thought it was the thread so tried a new rubber 'o' ring then ptfe. Eventually found it is the element itself and tried sealing it with silicone etc. which worked for a while but it's now leaking again and I just want to get rid of it. I figured a blanking plug will sort it as I don't want to pay £60+ for an element that isn't even connected.