Lidl/Aldi bike computer : How to mount on stem?

[RSV_Ecosse]

Got this lying spare here so thought I might as well put it on the MTB I just bought. It's one of the el-cheapo Lidl or Aldi ( can't recall where it was from ) ones. I'd like to mount it on my stem but can't work out how to change the mount part. It looks like it can be changed through 90 degrees in order to mount on the stem as there is a wee hole in the back of it with a sort of clip type thing that looks like a screwdriver is required to push to disengage it?. A bit hard to explain but hopefully someone that has one the same will know what I mean. Any ideas on how to rotate it folks?. Many thanks.

Oh, forgot.......it's this one :-

 

[Wobbly John]

Does it use cable ties to hold the mount on? I've got a similar one on my road bike stem - I just crossed the cable ties over under the stem.

 

[Bayerd]

Use cable ties. I've got the same one, got it from TESCO, works OK.....