ah, now I know with the mk2s, the 3 and 5 door FRONT seats were the same, only the 3 doors had the tilt levers on them - the mech is instide the seats on both....
A way to check would be to look at the bottom of the seat backs (from behind) and see if you can see the release mech for them to tip forward. You should be able to tip them forward by lifting the little pawls up on both sides... If that works (on your 5 door seats), you can take the suckers apart to put the levers in for the tip bit, the cables will already be there...