@User020367
Ok I’m hearing what everyone is saying about the dog being left alone for 6-7 hours a day but what do other dog owners do? Am I to believe all dog owners are at home all day? I find that highly unlikely!
You hire a dog walker in the middle of the day as an absolute minimum, or you send the dog to daycare. It's not nice or fair to leave a dog home alone all day - they are companion animals.
Lots of people work full time and own dogs, but they pay for care, or work shifts around their partner to minimise the amount of time the dog is by themselves. You're looking at about £10-12 an hour for a walker, or £20-25 a day for daycare.
As an aside - leaving the door open all day isn't a good idea and will only blur the boundary between inside and outside - you don't want an older dog getting confused and deciding it's okay to use the toilet inside.
If you are going to leave this dog all day, you need to first take a good chunk of time off to settle him/her in. Dogs don't always settle easily with new owners, especially at an older age. You may find he/she barks when left, howls, becomes destructive (and destroys your garden), digs and tries to escape etc.
Once you know the dog is okay and happy being left, you can then start building up the time, but 6-7 hours a day is generally considered way too much. Charities recommend 4 hours per day as an absolute maximum. While many dogs will be okay for a bit longer, you can't leave them that long without someone coming in at lunchtime for some exercise and a toilet break at an absolute minimum.