BBC iPlayer padlock symbol on some programmes

[egd1955]

Hi, just bought a Sony Bravia 8 TV (K65XR80U).

this evening I went into BBC iPlayer to watch Wolf Hall all the episodes have a padlock symbol on them and when I click on an episode it just gives a description of the episode and no option to open the padlock. I do not have parental controls set on the iPlayer or TV. When I went into settings on the IPlayer on the TV under parental controls it said it was honouring settings in my device! 
other shows didn’t have a padlock so it seems related to parental control!
fortunately I have an Apple TV connected so could watch it via this but I would like to unlock the programmes on IPlayer via the TV.

my tV is up to date in terms of software updates 

any ideas to solve it?

thanks