Pretty much says it really, popped in earlier and they had them reduced from £25 down to £17.50 - But remember they're £39 on Apple online so i thought this was pretty impressive.
Don't know if it's nationwide in ASDAs - sorry.
EDIT: Model Number is MB125G/C
Has adapters for:
iPod Video (5th Gen) 30GB
iPod Classic 80, 120 and 160GB
iPhone 3G 8 and16GB
iPhone 3GS 16 and 32 GB
iPod touch (2nd Gen) 8,16,32 and 64GB
iPod Nano (4th Gen) 8 and 16GB
iPod Nano (5th Gen) 8 and 16GB
Other adapters can be purchased separately.