The big problem with your question is trying to find a like-for-like comparison with your personal circumstances...?
To my perspective its more a question of evaluating numerous factors.. such as.. {in no particular order}
(1) What do you need to carry?
(2) What control do you have over what you may need to carry in the future?
(3) Are you personally marketing, selling, advertising your services direct to the customers who pay you?
(4) Are you just a sub-contracting link-in-the-chain doing work on behalf of someone else who has secured a contract of work?
(5) If you are working on behalf of a third party do they have any preferred standards for appearance of workwear and/or vehicles?
(6) If you have any half-decent swanky van, do you have a secure place to park it overnight, and/or to move any valuable tools out of it overnight? (As almost any type of van, plain or sign-written, is a magnet for low-life scum to try and open it looking for valuable kit to sell for drugs etc..)
(7) If you are working for yourself do you need the expense of running two vehicles, (e.g. van+car), or could a decent people carrier / estate car combine your essential work and personal transportation satisfactorily?
(8) If the majority of the time you only have to carry your own personal tools and test gear, then they will probably all fit comfortably into the boot of the average family car?
(9) If the majority of the time you are mostly doing only domestic related work, and/or fault finding, or EICR's requiring just a few tools and test gear, then they will probably all fit comfortably into the boot of the average family car?
(10) If you are doing significant amounts of industrial/commercial work where you also have to collect materials for the job then a decent van is an essential tool.. No options, or you will be loosing out on almost every job!?
(11) etc..
(12) etc..
(13) brain freeze as TOO much incoholic affluence...
Side note....
We are Midlands based and our 2016 reg, 1600 diesel family car... (used for towing caravan)..
is exempt for the congestion charge in B/Ham city centre.. and is only £30 car tax per year...
So I am Just guessing that an equivalent sized, 2016 van engine, would also be exempt from any congestion charges?