Wiring mini box

[kingy2]

I recently had a 360 box and a mini box installed. I'd like a second mini box but want to fit it myself after the mess the installer made. My question is when originally fitted the engineer ran the cable outside he fitted a splitter out

 

 

side for the two boxes can I fit a splitter after this to create the extra connection point or should I look for a splitter that splits the single cable into three outputs?

I have attached pictures of post installation to show why I don't want virgin to fit it. I can assure you my house is normally very tidy and I've marked where he just left the cable on the surface running across a doorway. 

[nodrogd]

You should not be altering VMs network wiring. It is a shared resource with all your neighbours. If any alterations you make cause noise ingress issues not only will your connection suffer, theirs could too. 

Adding cable & particularly splitters changes the signal balance at your property, which again affects your service. This can only be corrected with access to the street cabinet.

VM will not charge you for any cabling work if it relates to added services such as an additional box. “Tampering” with their wiring is potentially very costly for you if ingress is traced to your modifications.

[Roger_Gooner]

It makes no difference whether or not you want to add a splitter as VM will always send round a tech to do the split and add the cable for the additional box which he will provide.

[kingy2]

Thanks to you both. I have ordered an install on a day I'm off work so hopefully won't end up with the mess I did from the first install.