The reason why patterns used to be printed without seam allowances was so that you could put the pattern piece on the fabric and mark the actual position of the seams (then cut out around those, leaving enough extra for whatever seam allowance you wanted to use). If seam allowances are included in the pattern pieces, this requires you first of all to cut out with extreme accuracy and then to sew a fixed distance in from the cut edge of the fabric in order to hit the unmarked seam line. I find it a lot easier to mark seam lines and cut out roughly, then sew up by matching the markings. (It also allows you to skimp a little when positioning pattern pieces, if you can't quite squeeze the full seam allowance all the way down; it isn't always needed.)
Modern patterns are always printed with seam allowances on them, for some reason. I never worked out how to cope when the important regions of the pattern that needed to be marked were all hidden under the paper pinned to the cloth!
On the other hand, I only know one way to apply bias binding, and have no idea how to alter sleeve shape :-)
I'm surprised the pattern directions didn't mention the requirement for a fastener on the back opening, and specify it in the list of 'notions' needed to complete the project. Or perhaps another thing to learn from the Great British Sewing Bee is the importance of reading the instructions all the way through before you start! I admit I have a tendency to work down the list in strict order without 'cheating' by reading ahead... too much novel-reading, perhaps ;-p
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The reason why patterns used to be printed without seam allowances was so that you could put the pattern piece on the fabric and mark the actual position of the seams (then cut out around those, leaving enough extra for whatever seam allowance you wanted to use). If seam allowances are included in the pattern pieces, this requires you first of all to cut out with extreme accuracy and then to sew a fixed distance in from the cut edge of the fabric in order to hit the unmarked seam line. I find it a lot easier to mark seam lines and cut out roughly, then sew up by matching the markings. (It also allows you to skimp a little when positioning pattern pieces, if you can't quite squeeze the full seam allowance all the way down; it isn't always needed.)
Modern patterns are always printed with seam allowances on them, for some reason. I never worked out how to cope when the important regions of the pattern that needed to be marked were all hidden under the paper pinned to the cloth!
On the other hand, I only know one way to apply bias binding, and have no idea how to alter sleeve shape :-)
I'm surprised the pattern directions didn't mention the requirement for a fastener on the back opening, and specify it in the list of 'notions' needed to complete the project. Or perhaps another thing to learn from the Great British Sewing Bee is the importance of reading the instructions all the way through before you start! I admit I have a tendency to work down the list in strict order without 'cheating' by reading ahead... too much novel-reading, perhaps ;-p