its not that simple
you have to weld / bolt it in. but you will more than likely need to remove the existing runners off the floor of the van
(spotweld drill and a parting chisel)
then weld em to the new swivel base.
thats why westy bases are easier to fit. it just welds in with no need to remove anything cos the seat runners are already there on the swivel base and the actual swivel is designed to weld inbetween the existing runners..
I bought one similar to the one shown in JK second hand which has the seat runners already integral with the top. I don't know if the JK ones are a no hastle interface or if they inviolve cutting and welding. I welded "U" shaped 8mm bars to fit under the original runners the bottom at the front and used 8mm nuts and bolts at the back. It adds a bout 20mm to the seat hight but that suites me. Otherwise the man is right you may have to do some runnere unpicking and rewelding I fear. I don't think yours is a T25 jobbie.
Cheers
Wolfie
Well-timed silence hath more eloquence than speech.
"A quiet shy boy who took little part in games or sport"
88 High top 2.1 WBX