Hi steveelec
There are a few corruptions in your import file - open in notepad and scroll down to about the 15th item - you will see some weird stuff - this can throw out all subsequent imports. This continues further down the file.
Take care when importing, a bad import cannot be 'un-done' - practice on a sample file or in a copy of your file. If this is not possible, take a backup before each import. Import 2-3 items first, then check.
Check if the first 10 or so items imported correctly - if no, then it might be how you mapped the fields - even if you use automatch, you need to scan the mapping to see it was done correctly.
There are importing and exports help articles in the Support centre.
Regards
Gavin