We've had single foxes visiting our garden for years, they never did any damage, one liked to sunbathe on the rockery. This is Fiona, as we called her, she was a frequent visitor to our garden around February 2017. She's having a drink from our frog pond. I only took photos of her through the French windows or the kitchen window on zoom. She'd come into the garden, stand in the middle of the patio and look at us through the French windows. We didn't shoo her away. She'd stay there for a few minutes then she'd leave. She did this on several days over the next couple of weeks, we still didn't do anything other than watch her. She then seemed to disappear, with only an occasional fleeting sighting at the bottom of the garden. But at the end of March I looked out the kitchen window and saw this. She'd given birth to six cubs under our tea-house. There's about 9" of clearance under it as it raised on small brick piers. We think she was checking us out in February to see if we would be a threat. She'd got in under the back where there is no "skirt." These are Victorian style skirting boards on the other three sides, attached to the base but clear the path by a couple of inches. With the big gap at the back and a small one on the other three sides, there's good air circulation under the building. She was an excellent mother. I supplimented their diet by leaving out some cat food in a bowl next to the tea-house each evening as I thought six would be hard to feed. They always looked well cared for and clean. They grew rapidly and were quite inquisitive. We left meal worms out on the patio steps for the birds, but they'd pinch them, but "check with us first to make sure we didn't mind." and if there were none there, they'd look in through the window. They came out at dusk to play, at first but later got bolder, they'd either chase each other, or practice "pouncing," off a sturdy up-turned box I left out for them. In July, she took them out of the garden two at a time over three days. She showed them how to get over our six foot fence by first jumping up onto the top of the Japanese lantern next to the rockery. After they'd left. I concreted over the ground between the back of the tea-house and the rear fence and made a wood and wire mesh screen to cover the gap. To prevent access the following year. She did come back at the beginning of this year, to check out her old den. She'd tried to do a bit of digging in the three inch gap between the path on the right-hand side of the tea-house and the skirt but gave up. There was no way she could get under again. There were alway muddy footprints on the veranda of the tea-house and on the bottom windows in the doors. But we didn't mind, as they provided a lot of entertainment. "But once was enough." Here's a video. They used to set off the PIR on the corner of the shed, but it didn't bother them.
She obviously knew your garden was a safe haven to bring her cubs into the world. They all look fit and healthy and I hope they've all survived.
Here's a few more photos. For a while Fiona had a bad eye, probably got into a fight with another fox, but it got better. When small their fur is very "downy." "What have I told you about coming out in the daytime when I'm not around?" This is my favourite photo. It was taken at dusk so it's not very clear. Look at the mess on the tea-house varandah, but it's just muddy paw prints from all the jumping off it they were doing. The tea-house experiences extreme temperatures during the year. My jukeboxes don't like to be too hot or too cold. In the winter I have to cover them with insulation and keep a 60w inspection lamp burning in the bottom of each cabinet. In mid-summer it can get really hot in there, despite me opening the vent in the roof and there being two more with insect screens near the bottom of the back wall, so I open a door first thing in the morning. I couldn't have a door open while the fox cubs were there. So I fitted this extractor fan in the roof space... They left a week later! They liked to play "chase." Fiona brought them in kids' toys that neighbours had left out over night. Small balls of different types, little soft dolls, plastic toys, a Manchester United Red Devil mascot (that amused me) They'd tear around the garden chasing each other for them. One afternoon my wife shouted "Quick! "Quick! One's got a blackbird in its mouth and the others are chasing it!" They were running round and round the koi pool chaasing the one with it in its mouth, (I'd put a net over the pool once they started coming out from under the tea-house, in case they fell in). There was nothing I could do for the bird, we get a lot of them in our garden. I said, "It's just nature." But she was quite upset. Next morning I had a walk around the garden, but couldn't find one feather, but I found this in the middle of the lawn. So panic over.