There are four well set out  EV charging bays at the end of our village and they look the business. Every time I walk past them the spaces are filled with different ICE vehicles, nobody uses them, quite amazed that no one uses them.

https://www.ebay.co.uk/itm/281147951739?itmmeta=01HYNMKQ8ZRZXEP2CVVBZQ4Y44&hash=item4175b94a7b:g:xW4AAOSws5FcrHtr&itmprp=enc%3AAQAJAAAA0AyzyyvbUyFrP0nOq3Exf9neiP1Ntrjx1jaBNHBEl%2FZoN8COfNSjyToT0p97B7dXcy0IduXZxm6s4ws541TrpZqxX%2B3E02O4rOJHxh6576eFoTkjXjf5PtfqIDdLHtOkIX3vfqa%2Bcr7laKWrhMjCdUVSQf%2BPu%2BrEuhvzxt0lSmgqPCN6UdTZKPUg%2BMGgvnZtJInzkgRZHv9W%2FmfIczKNd%2BcMJdJJAJaIuw3NqHM%2F7TEx1%2BhK2gpiuwrNYAkXobgxTpf2zHUjRTfHd9v0sgZTvSg%3D%7Ctkp%3ABk9SR-r0zrT1Yw

https://www.ebay.co.uk/itm/281147903336?itmmeta=01HYNMP8F0EAPG49P56SFNS1AG&hash=item4175b88d68:g:eJYAAOSwIq9crH-d&itmprp=enc%3AAQAJAAABAIOUUPTOWjwhEu7lfrzg6ZUDPtX7aAiiIx6IuoHtFYEIsbiYvS3xUCTLI%2F5jOzsJCGrmCJtFLUpLuHyN1MrA3RMXHogrKdnAkt3nGJx6TtzMRzUuDVPhPLA5ULOKBXl57ADTWN6RrUx5owQIAeVMl933W%2B6Hm81dZ1pWPC9r5NVcR7JQd5vHDhTgjYzyB4sclvl2HyfFjp0c8kJJ%2F3tJ7EwOAXOdAkCf5Er78HkXMEQDFeUCT2EQF6aHyAAlvLySqs566rBK4ZGN5TJnf9FFtxJ763wiQeJFs8%2Fzw6tkpqAZk4eCE%2FCsoGc99Dbirh6rOCIGbDYlfm%2F8Bt%2BlHw9fwWo%3D%7Ctkp%3ABk9SR8iH2bT1Yw

Using these you can change nozzle on the lance - turbo to 15 degree - hi/low - foamer etc..

nozzle size is dependant on pressure and flow - 21 Ltr 200 Bar would be an 065

here's a chart
https://www.flowjet.co.uk/pressure-washer-nozzle-chart

https://www.ebay.co.uk/itm/186183609327?itmmeta=01HYNK7G0F0XEDSWTHQT5QHCTQ&hash=item2b59686bef:g:S0EAAOSwF0Flip6~&itmprp=enc%3AAQAJAAAA8NV8TLHHVGshfTUazt8RLvS%2BONzQYfveTSZgyS%2Fak6g7cUxmTAJngNMiBtMjflg9ROfSeFRTelAS6gQVRgtpiScQgx7mD%2BOvndA7JzlE7S%2BEUnnLkXEwLPlM8vX%2BJtljgKCt56HT65K%2BgF2t5drxTyYSpyFNl6cJxcRvDw1p8ejN0wDNm%2FlVC63id%2FXCx4DebYKvqIvO7NXR0uxIBJ7TfRwT%2FrTrZBfjurw%2FmMJYLVtjMgGphs0kkf78rlr3XPgpGbDWJzifeMTsXJgZf2aumS%2FR1BHPbnTMABzSwRu976ygzzsjiuG%2FU4vhdjlKfNxRNQ%3D%3D%7Ctkp%3ABk9SR7CAnrP1Yw

for standard 15 degree nozzle I use whatever make my local supplier has - turbo needs to be a good quality and they last

Yes 120 is far to small - your drawing at 21 litres per minute - if flow is poor you have as little as 6 minutes run time
most places seem to have reasonable flow of 15 but thats still a deficit of 7 litres a min which gives you 25 minutes maybe ? before your empty

Chemicals:

Hypo
TFR
Graffiti cleaner
Brick cleaning
Oil Stain Remover
oxalic acid
plus several other chemicals as you come across various works

I use different places as some products are better than others

thanks again all for the replies.

one question i have is regarding the way everything connects. I understand quick release is the way to go, however seeing there's more than one type. i assume it's the midi quicck release most equipment uses? rather than the 'large quick release'?

regarding chemicals, it seems the basics required are hypo, surfactant, biocide, oil stain remover, rust remover. does this cover most requirements? do people tend to buy all these solutions from different suppliers or all from one place? with carpet cleaning it seems most suppliers do some sort of variety of every product required which makes it nice and easy. is that the same for jet washing solutions?