The usual rate of sale for the round only is 3-4 times monthly income, The van and equipment is a personal common sense thing, don't kid yourself that because it has got a £300 tank in it and a £250 facelift pole that is there worth, as second hand these drop remarkably quickly especially when sold as a job lot!! Price it to sell not to field enquiries from messers.
Which brings me on to messers and timewasters, the world is full of these types who want to but either can’t or dare not set up and take the plunge, give yourself plenty of time to get the deal done and always keep contact details from enquirers.
Try selling on here, there’s always some for sale on Ebay and Gumtree so have a go on there, there is another site who have a paid page for just window cleaning businesses for sale but as I think it’s a rival to CIU, so I am not going to post a link, you might try a search though.
Good luck Phil.