I'm a cleaner. Been in the trade for 5 yrs now.
I'd say, a house that size, including bed changing, you're looking at a 5-6hr slot each time. But to give you a more accurate time, I'd have to do a home visit first to see the size & layout of the property and the overall condition of it.
If the property is in a 'neglected' condition (as you say) I'd recommend having and extra hour as well, for the first 2-3 cleans, to bring it up to a standard where it can then just be maintained each week.
I do bed changes, but I offer housekeeping services too. Not all cleaners do. Some just offer cleaning and that's it.
A house that size, with young children and busy working adults, I'd recommend weekly cleaning. I'd only do fortnightly for small flats and bungalows with an elderly couple etc, as they don't lead busy lives.
The cost for general weekly domestic cleaning varies depending on the area you live, and the experience and expertise of the cleaner. I'm experienced, know my stuff, fully insured. run a legitimate tax & NI paying business, have many many business running costs, have an accountant etc. So I'm not the cheapest in the area. But I have a very good reputation and word of mouth has always been my source of work.
You can get far cheaper cleaners than me - often people just starting out, think it's easy money for just wafting a duster about, want cash in hand because they don't want to pay their taxes. But they don't last long when they realise its actually a lot of hard graft, both physically and mentally.
Ask local neighbours, or on local Facebook groups, or the Nextdoor app, who they'd recommend.
You'll pay more for a company who runs a big business, as they have staff to pay as well as turning a profit. The upside to this, though, is if the cleaner usually assigned to slot is ill, they'll send a replacement. And this can happen a lot. Cleaning companies staff turnovers are frequent, so you'll find in the space of a year you'll meet lots of different cleaners, all with their own varying standards and enthusiasm for the job.
You'll pay less for a sole trading independent cleaner, and they'll really get to know you and your home. How you like things, the most efficient way to clean it to the best standard, they'll learn what needs doing every clean and the tasks that can be rotated. As the business is entirely theirs, their enthusiasm and standards tend to be much higher. The downside is though, if they are off for illness, or any other reason, you have no cover. You just have to donit yourself until your cleaner returns.