Buddliea help needed

I swear my local garden centre is trying to fob me of

Last week I popped to the centre and asked if they sell Buddliea Buzz and know they didn't so went the following week just to look around and now have them in stock only thing is I believe they are just regular big daddies as they were all nearly three foot tall with really fat stems.

I have one at home that looks tiny compared to these is there anyway of telling the difference between the two.

 

Scratch that,

Just realised I have the chip version with grows to two Feet Buzz grows to five feet.

So much to this gardening lark.