Overblankets should be used on the lowest setting, but will provide a warm layer.

Silentnight Comfort Control Heated Throw - Fleece Heating Overblanket Electric Heated Throw - Luxury Machine Washable Blanket for Sofa and Bed
4.0
Amazon.co.uk

Dreamland Intelliheat fast heat up Luxury Harmony Soft heated Overblanket double, electric blanket 180 x 180 cm, 2 controls, 6 temperature settings and...
4.0
Amazon.co.uk

CORIWELL Electric Blanket Heated Throw - 160 x 120cm Flannel Heated Blanket - Grey Heat Blanket, Fast Heating Electric Overblanket with 10 Heat Settings &...
4.0
Amazon.co.uk