Just use a Citroen one strait fit you can get them on ebay then you need to get it switch on
Give the forum a search. There are a number of posts on adding a cruise control. Some are quite detailed.
2010 Berlingo Multispace HDi 110 with FAP. Persamos green.
You need the stalk which can be had off ebay - the prices range from £10 to £50+, Search for either Citroen or Peugeot - I picked mine up for £15 and was from a Peugeot 206
There are two types. One is just Cruise Control and the other is CruiseContol/Speed Limiter. Both will work, but without a change to you accelerator peddle (£100) the Speed Limiter function won't work on the second one
Looks like this
Here are couple on ebay at the moment, but there are loads more.
Then you need to get it activated either by a main dealer, or if you have access to a Lexia/Diagbox you can do it yourself and save a few quid
Here is my guide
on how to do it and Citroen's original documentation