Sue, the SHAKS sig is very very hard to find but it will be there. I had to hold one of mine under a strong led light last night to even see it faintly. It definitely could not be seen with just daylight and I remember buying it and thinking it wasn't signed, so to find the sig last night was a revelation

I am pretty sure this is a Will piece and from the Crunch range but the sig doesn't look like those on my pieces - so you might be right.
I'd been looking for Della's bowl as well. Maybe Della's bowl is Glasform as well perhaps as that has a similarish sig to this one?
hmm.
Crunch range here - but there are a variety I believe and he has been doing these for a few years so there will be variation:
https://shakspeareglass.co.uk/collections/crunch-1I went on a glassblowing day with Will. He is fabulous

(though the Crunch range and shapes are not my cup of tea - but he does some other pieces that are simply utterly beautiful to look at, some of which I have, but couldn't afford the piece I really wanted)