I swung the dart closed and allowed the bottom edge to open up. I taped it temporarily as I'll use the dart line again later! Thanks to my fella for providing a finger in need - he is fascinated with how I do this stuff and is always willing to help - bless him.
Next I sliced up to the shoulder and open up the amount needed. My full bust measurement is 4cm bigger than my high bust measurement (which doesn't technically make me a 'D' I know, but it's what I need to wear anyway!). This means I need to add 2cm on each side of the bodice, so I opened up the pattern by 2cm.
Still with me? Okay, good. The next step is to take into account the added length of a full bust (the previous step took care of the width). I measured the pattern from the shoulder, through the bust point to the bottom edge and worked out what I needed to add based on the measurement I took earlier. This was 3.5cm. I opened the dart again and this time opened it up at the bust point instead of the side edge, by 3.5cm.
Oh, I really hope this is helping, I'm starting to feel confused on your behalf! Next I cut through to the centre front and dropped this piece down by the same amount.
Finally, I patched all the gaps and re-drew around the pattern piece. Remember on the bottom edge don't just join the gap with a straight line, you need to measure the cut edges and keep this length consistent in the new section (sorry, that's not really clear but I don't know how to write it). You can see how my bottom edge has a curve in the new section. Try to visualise how that will look in three dimensions and I think you'll see why it needs to be this way.
I would normally re-trace the pattern but I've run out of butter paper so this is my actual pattern piece for the time being. Must remember to get to an art supply shop before Christmas!
I'll cut and sew the lining today as a kind of toille, then if all goes well I'll get cracking on the main dress. Wish me luck!