im fine with waiting with as long as you need
I have reloaded the pdf. It is now 50 Mb, instead of 947 Mb. Hopefully that sorts all the issues.
I still do not know how it got to 947 in the first place, the AfPub file is only 16 Mb! I think it must have been some feature in the Export to pdf function. Instead (this time) I used the Print to PDF function, which got it to 90 Mb (which still seems weirdly high) and then used a file compressor to get it to 50 Mb, quality of the pdf still seems good.