I, too, went through like 18 months in the UK with the big stores not selling any until one reintroduced it recently. Alternatives on the internet were like 3+x the price, at least. It was incredibly frustrating. I now stock up and have 2-3 boxes of the stuff, in case it does vanish again.

Doubly frustrating since mine is a small, single-drawer dishwasher, so pods are even worse since I can't break them down. It leads to me having way too much detergent in the dishwasher and I end up with residue on the dishes.

The big Sainsbury's near me never stopped doing this:

https://www.sainsburys.co.uk/gol-ui/product/sainsburys-conce...

And this has worked for me too:

https://www.waitrose.com/ecom/products/essential-dishwasher-...

Or… use a (dirty) knife to split a solid tab; put 2/3 in the dishwasher compartment and 1/3 just in the dishwasher.