18 Week old Cavapoo Potty Issues

My 18 week old Cavapoo, Roy, is an absolute angel. He is sweet, sociable and a pleasure to be around.

Training wise he is great in the crate – sleeps through the night without issue. He happily goes into his crate on command, sits for meals and has recently got much better at recall.

He has however regressed in his potty training. I was very ill recently (sofa bound) for a week and he has lost all sense of toilet training.

I take him outside first thing 10 minutes and he doesn't go. Pees as soon as he's inside. He'll poop when no one is around and just sits outside on the grass when I take him out.

I wait 5-10 minutes after every time he enters or exits his crate and he just won't go outside now.

It has been extremely wet in the UK recently and rained for 40 days also which doesn't help. Anyone have any recommendations? He was doing so well but seems like his routine is completely out now following me being ill.