OneZeoN
Enthusiast
I would phone them and explain the situation again and ask politely but firmly for either a cancellation or replacement.
If they argue you could point them at this very thread / their own forums because as Oussebon says, there have been other reports of the 17" model having similar/the same issues.
Ultimately the device doesn't appear fit for purpose and it falls on the seller to prove otherwise.
Thanks
They said today it's finally with a technician so should be "fixed" shortly.
I'm happy enough (I think) to let them return it to me and I'll test it to make sure I'm happy with temps.
If I see ANY overheating I'll be 100% be returning and demanding a different model