According to Witter's website, the towbar is the same for the 3 & 5 door (not type R though)
I have one of their twin bolt bars fitted, as the fixed one has an invisible bumper cut. The removable one is twice the price and has a visible bumper cut (take the point out of it being removable IMO).
Here is a link to their website... includes fitting photos too.
Witter Towbars - New ECApproval Towbarto be Introduced Fixed bar
Witter Towbars - New ECApproval Towbarto be Introduced Removable bar