But I decided I needed to stop worrying and just make something. So rather than deal with the stress of a bought pattern, I pulled out a top I liked but no longer fit and made my own pattern by copying what I liked and adding what I wanted. My mum happened to be staying over while all this was happening and as she is a great sewer, was able to offer excellent support and encouragement.
Anyway... after not too many hassles, this is what I came up with.

I am really happy with my new top, but the best part of this whole process is that I did it without worrying about perfection, following steps and what might be wasted if it didn't work. There is hope for me yet!