I've had a few e mails from Europe asking for measurements for my bag in centimeters, and a bit of clarity for the zip insertion, so hopefully this is the answer! Please still watch the You Tube video, link in a previous post, as I think it's clearer to be shown how to make it rather than written instructions...
The lining is two rectangles of fabric measuring 46cm x 29cm,
and two rectangles measuring 46cm x 6cm
The outside of the bag is made up of two rectangles measuring 46cm x 33cm
the handles measure 46cm x 4", folded in half, press the edges inwards by 1cm and sewn down the sides.
My zip measures 50cm but I will cut it down a little, this is sewn into four strips of lining fabric, each measuring 36cm x 6cm,
The pocket on the front of the bag measures 23cm deep x 22cm wide, my zip is 23cm, I'll trim a bit off this, and the support for the zip is a piece of spare lining fabric measuring around 20cm x 10cm.
Draw a box on the back of this piece measuring 1cm x 15cm.
place this section centrally towards the top of the right side of the pocket and sew all the way round.
cut straight down the centre of the box, stopping 0.5cm from the end, and mitre your cut into the corners, careful not to cut through the stitches.
Turn the right way out and press, You should have a neat hole in the middle of your fabric!
Place your smaller zip behind the hole, pin, tack and sew as in the video.
Fold the edges of the pocket inwards by 1.5cm and press.
Pin the pocket centrally to the front of the bag and sew all the way round.
Take the four strips of fabric that will hold the long zip, and press the short ends under by 1cm.
sandwich the zip centrally between two pieces of fabric, line up the edges and sew with the zipper foot on your machine.
Fold both sides open to expose the zip, and press.
Repeat with the other side of the zip, I've top stitched along the zip to neaten, then top stitch across the ends of the fabric strips, avoiding the teeth of the zip.
Make a couple of little pockets and sew them to the ends of the zip as tabs. [I cut about 3cm from the ends of my zip first]
Take the large piece of lining fabric and lay it right side up.
PLace the zipped section on top, centrally, with the slider of the zip facing up.
Lay the narrower strip of lining fabric on top, right side down.
sew across the top, then open up and press.
Repeat with the other side.
This is how the top of the lining of the bag should look.
Take the front of the bag and pin or sew the handle facing inwards in line with the pocket, then do the same with the back of the bag so that the handles are in the same place.
Sew the top of each side of the front of the bag, right sides together, to the top of the lining section.
This is how the bag now looks.
Fold the right sides of the front of the bag together, and the same with the lining, then sew all the way around the edge leaving an opening of about 15cm across the bottom of the lining for turning.
Make the base of the bag square, it's easier to watch the video than me trying to explain this in writing, but basically your stitch line should make a triangle 5cm from the point of the corner.
Turn the right way out, then sew together the opening in the lining either by hand or machine.
Press, then top stitch around the top of the bag to make neat.