The 2010 Octavia I have my eye on only has one key, so any recommended placed for a spare key?

You could try the dealer route as I did but they but they held my vehicle to give it a health check and a valet, which I had not requested and was not told about when I booked for Key programming.

I had a medical appointment booked so needed to leave within the hour, they listened and curtailed what they were doing so I could leave.

They offered me a free valet in recompense.

I sent an email to head office suggesting than anything other than requested and booked should be mentioned at the time of booking.

This I think they now do.

 

I therefore suggest any local key cutting company's to supply and programme one for you.

 

That would be a cloned key, if there are any doubts that the original missing key might be in the hands of questionable people then the more expensive main dealer route is the way to go.