I had this problem with the bulb thing on top of the Provado. In the end I took a knife and cut off the top of the bottle and used the old measuring cup which came with the old bottle.
I think the ones i used to buy are 6 inches tall. They were ideal for long rooted things, like Hellebores and various shrubs. Congleton Plastics used to make them 20 years ago which is the last time I managed to get some.
LBS Plastics are very good suppliers.
Lot of complaints about Celandines, but I like them,, especially these.
Ficaria verna Poached Egg
Ficaria verna Collarette
Ficaria verna Double form
Try buying tall 4 inch square ones. No-one even makes them any more from what I can see.
One of the nicest sounds there is.
If you tied the leaves last year then that is why they are blind this year. As Bob says, leave them well alone.
Some from today
Feed them is the answer. Give them a good dose of a low nitrogen food (Tomorite). Blindness is generally caused by hunger, so you need to build up the bulbs for next year. Moving them will not really help.
Wait until the potatoes are ready to harvest and then eat them. There will be nothing wrong with them. We frequently dine on 'volunteers' like this.
Add some washing up liquid to the Roundup, it makes the stuff stick to the leaves so that it can be absorbed before sliding off.