How to make sure this towel tail lock shield is off?

[Peter T]

Hello Everyone

I would like to drain the towel rail in my bathroom and add some inhibitor. I have unscrewed the chrome cap on the lock shield and there is no spindle that can be turned.
How can I make sure the lock shield is closed off before draining?
Please see attached pictures.
Thank you for your help in advance

 

[gmartine]

You need an Allen key to close that valve.

 

[Peter T]

Hello Gmartine

Thank you I brought a 4 way radiator spanners and none fit so I will buy a set of allen keys

Thank you for your advice.

Peter

 

[Jerry]

I hope he some spanners too

 

[Peter T]

Hello Gmartine and Jerry

Thank you for your advice and help.
Had other spanner’s needed. Job done
Thanks again