This deal is definitely a long shot without a doubt and I understand why it will probably be super cold but thought it is interesting to post.
The LEGO Minecraft Pillager Outpost is showing up as £0.00 on the B&M app and when the barcode is scanned via the app it too shows as £0.00, weather this will happen on the stores checkout idk but if your planning a B&M trip try it out and please confirm in the comments
I'm going to sound proper hypocritical on this one as I had a go at someone else who posted this set as being £8.50 because B&M mis-marked it but when I scanned it at that time it was £28 this time I've scanned it and it shows as £0.00.
Scan this on the B&M app should show as £0.00
I understand if this gets cold
worth a try though