Good morning

apart from the £150 cheaper Britpart price....what else is the difference?

Is one bluetooth and one not?

Britpart used to sell the IID, but no longer do so. They sell another diag product, which I have no experience of

If both are brand new, the BP item is not an IID, and not as good

If its a 2nd hand item, it could still be a proper IID, but at that price, I'd expect it to be a non BT unit

We need a few more details

This one at p38spares.....my phone is not letting me add the link for some reason.it is new and BT

Click image to enlarge

I would say that’s the non-Bluetooth version, as the BT version has a flashing led on the front.
It should also say “Bluetooth” on the label, which that one doesn’t as far as ai can see. Got - 2017 SDV8 Autobiography in Loire Blue
Had- 2008 TDV8 Vogue SE in Java black
Had - 2007 S/C in Stornoway Grey

Looks like an old stock, non BT model

Britpart haven't stocked an IID Tool for over 3 years now...