You probably must have a van. Though here's a tip RG Francis never asked to see my van. Bg would expect to see it.
Anyway I recommend get a clean tidy Combo 2004 or so for less than 2g white.
Tax reasons it is much better to run a van a lot easier to prove you don't benefit in kind from it, so you don't get taxed on it.
But you can get a contract first then buy the van.
Or lease one but be aware there are mileage restrictions.
If you can afford a new deal the old style Berlingo is only 7k incl vat 1.4 petrol. New tax laws you can claim 80% of that price as tax releif in year one even if you are paying on hp. You still get tax releif on the interest.
Furthermore get vat registered. The companies you sub to are registered. Then you A/ get the van's vat cost fully back in year one but B/ look a much more professional outfit in all your dealings.
It doesn't put your prices up 15%, it only puts your added value up 15% and that only to private customers which you should keep to an absolute minimum anyway as all they do is come on here asking "our plumber says this what do you lot think? ungreatful so and so's!"