I've got a 13 month old beagle who, I thought, was and should be housetrained by now. However, over the last few weeks she's had one or 2 'accidents'. I say 'accidents' because she's only been left for a couple of hours at a time so there was no need for her wanting a wee. She seems to be reverting, almost, to her early puppy-hood. Any comments/advice.
She's not left on her own as we have 2 other dogs and the max amount of time is about 3hrs.

She could be attention seeking Do you react when you find the puddle ? If she is attention seeking any reaction from you will be her reward. Best to clean up the puddle & ignore her & use a biological wash liquid to remove all the scent from the place she peed on

Or could she be due to have a season ?

I don't say anything to her - just clear it up and send her out. Luckily the kitchen is tiled so it's easy enough to clean. She had a season about 2 months ago but she's still showing signs of a phantom - teats still a little swollen - although we have been giving her Urtica Urens for the past 10 days.