Hi GeoffHulme,
You may follow these steps & check if it helps:
a. Insert the DVD on your computer.
b. Double-click on My Computer.
c. Right-click on your CD/DVD drive, and then select Format.
d. In the File system list, click UDF format.
e. Click Start.
f. Click OK to start formatting.
g. Click OK again after format is completed.
Hope the information helps.