I've just discovered that my BIOS is version A00 that's probably been there since manufacture and would like to update it. The download of the last/latest version would appear to be A11, with the caveat being thus:
Product not tested for Windows 10 upgrade
Dell is not testing or developing Windows 10 drivers for this product. If you choose to upgrade, some features, applications, and connected devices may not work as expected.
As i did upgrade to Windows 10 a while back i'm concerned that this may not work and potentially wreck the laptop.