How to clean a filthy patio...

[CleanShirt]

Without a hose or a jet wash?

Basement flat with a sunken, walled patio. It's absolutely filthy. No outside tap and no hose.

Any options other than a broom and elbow grease?

https://www.amazon.co.uk/Spear-Jackson-Spray-Concentrated-Remover/dp/B011KT373Q/ref=asc_df_B011KT373Q/?tag=googshopuk-21&linkCode=df0&hvadid=696285193871&hvpos=&hvnetw=g&hvrand=15972965710452040336&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9044950&hvtargid=pla-2281435179018&psc=1&mcid=12ebe41a7f5a3057bc3d7044e44c5600&hvocijid=15972965710452040336-B011KT373Q-&hvexpln=74&gad_source=1

DH used something similar to this. Worked very well.

Can you hire someone?

I was looking at patio cleaners but it's literally just dirt out there (concrete floor) so wasn't sure if it would work?

Hot, soapy water and a stiff brush.

My mum hired one recently and they brought the jet hose with them and cleaned it up. Might be worth having a conversation with them and see what they suggest.

No outside tap - and brand new carpets so don't really want one trailing through the flat!

Bleach and hot water! Patio Magic?
Otherwise maybe paint it

At this time of year I would use the stiff brush and soap and water method, in the Spring I'd get someone to come and do it professionally.

Bio washing powder, hot water and a broom.

First, when the surface is dry, give it a really good sweep. If there is moss between the slabs scrape that out and dispose of it too. Get rid of as much loose dirt as you can. This is because dirt + water = mud. Once you've got all the loose dirt away, use a spray and leave it type cleaner as mentioned up thread. My cleaner of choice is Wet and Forget.

I would spray (or watering can) it with Wet and Forget, and then see how it goes for a month or two. Take photos for Before and After - otherwise you may not notice gradual improvement. I find Wet and Forget is great, but it takes a while.

If it shows noticeable improvement, but isn't completely clean, then I would treat it again in the spring. And repeat annually or as necessary.

The good thing about Wet and Forget is that it's very easy and quick and convenient - you just put it on and leave it (clue's in the name). This is why it would be my first go-to. It's not instant, but gives great results gradually in my experience.

@Noseyoldcow cross-post!

Thanks all. I've ordered a hose and a kitchen tap adaptor and will tape up my new carpets! It's that dirty that I don't think buckets will cut it. Elbow grease and fairy liquid it's looking like!

jet wash is the only way. I bought a cheap one at screw fix for £50. Brilliant