Hi Chrys,
Just an idea here but many years ago I went looking for Silica Gel for my telescope & eye pieces.
Luckily, I worked for a Co. that serviced photo copiers, faxes & other office M/C's.
The crate/s that they were packed in all contained 1/2 lb packets of Silica Gel.
I grabbed quite a few of them, so maybe check out a Photo Copier Service/Business Machine shop or 2?.
The other place you may get smaller packets from is any shoe store.
Most, if not all shoes have a few packets of Silica Gel in each box.
Ask them nicely to save you some & you may end up with more than you require......eg; A shoe box full.
HTH.