As per the title really!
Double electric blanket made by Silentnight - £14.99 at Aldi. Has 'comfort control' on the packaging. Seems a good price for a double blanket - selling on Amazon for £35.98 - and it's a brand I've heard of too!
Blurb from the box...
Silentnight Comfort Control Electric Blanket
Takes minutes to warm your bed - then you're in control
Polyester fabric is easy to care for and durable
Take control with simplicity and convenience
3 heat settings
Simple and easy to use
Warms your bed in minutes
Corner ties for easy and secure fitting
3 year guarantee
Not sure if it's relevant but when it scanned it came up on the till as 'single electric blanket'. The packaging and item are definitely double and the price tag above it with £14.99 on said double too.