Just picked up one of these monitors from Asda Abbey Lane, Leicester (Currently £70+ at a lot of online retailers). They have quite a few baby items heavily reduced! Also picked up a Graco Assure Car Seat for £10 (currently on sale for £69.99 in Argos)
I asked the checkout assistant if this was national and she said some stores are clearing their stock so pot luck if you find one, but if you do there are bargains to be had folks!
Other items which were heavily reduced were:
Britax Prince Black Thunder - £80.00 > £5.00