OcUK wouldn't cheap out on the paste. It wouldn't make sense for them to do it.
Most likely is it got moved in transport.
Attaching a heatsink as you've found out isn't incredibly difficult. 60 isn't a good idle temp though it isn't a terrible one.
What is important is if the machine is stable, and if it's a decent load temperature, idle temp is just a vague indication.
You should speak to OcUK support and ask them what to do. In my opinion it's fine for you to use the PC for now.
Most likely is it got moved in transport.
Attaching a heatsink as you've found out isn't incredibly difficult. 60 isn't a good idle temp though it isn't a terrible one.
What is important is if the machine is stable, and if it's a decent load temperature, idle temp is just a vague indication.
You should speak to OcUK support and ask them what to do. In my opinion it's fine for you to use the PC for now.