Extra early potatoes

Having a different thought re potatoes. 
I'm wondering about trying to force some extra early new potatoes. I have no green house but do have a couple of thoughts. 
Option one - potato grow bag tucked against sunniest south facing house wall I can find, filled with compost. Wrap in a couple of layers of fleece. Water compost well with hot water to get some more warmth in then plant spud in centre of warm compost. Cover top with fleece.

Option two - grow more normally in our detached garage, its not heated but I've never seen any frost in it. Light in garage is mainly from east facing obscured glass garage door and south facing pedestrian door, all are half glazed only. 

The potatoes I have are Nicola and that's all I'm planning on using this year. Anyone any thoughts?

The Hotbin comes with a "hot water bottle" that you fill with boiling water and bury in the compost to start heating it. Maybe you could do that with your spud compost. Make sure the bottle is suitable for boiling water first.