Another major stage has been accomplished. Yesterday I went to see my chosen printer, Brynymor Digital Press. Richard Harper himself spent time with me discussing my requirements and answering my questions.
The good news is that the way I have formatted the book is exactly what he needs for printing, so there is no need for any changes, and no need to pay them to design the layout. I just have to save it as a PDF file. He will also convert my ISBN to a barcode and put it on the back. The cover should also be a PDF, and the price for colour is the same as for black and white, so I can tell that to the graphic artist and set him to work on it.
The other good news is the today I received the printer's revised quote for the job, and it is well within my budget. So it's full steam ahead.