Also.. Run a hem about 1cm off the back of the cover.. Now, same again. Run your piping around the edge.. But start it at the v cut, and leave about 5-10 cm extra each end.. Lay your seat base front panel ontop, face to face, start sewing from the centre line out wards.. When you get to the ends.. It will look like this., This^ is where it's gonna get tricky! take your time and slowly sew all three layers together neatly, trim off excess piping, and any excess material, turn inside out and done!