It seems Twiglets are craftily phasing out the 150g bags and replacing them with 105g bags but not changing the price !
I found these at the weekend in Morrisons LOCAL in Blackpool and again just now in my Morrisons LOCAL in St Albans.
The ticket is marked Reduced to Clear but that's 2 stores I've found them in now.
Just to clarify this is in the smaller Morrisons LOCAL stores not the bigger supermarkets.
In the Morrisons supermarket and online they are selling the smaller 105g bags for £1.