... whether to have Electrician under my name or Electrical on the van.
Definitely "Electrician". I have been marketing electrical training and to electricians for over 2 decades. Here is my advice, reasons for choosing electrician...
The world is computerized, even if you are not. Everyone uses a the internet, even if they don't have a computer, they do internet search via their phone. Add to that fact, marketing 101, know your customer. The result is those first starting a business, do key word search to find what most people type when searching for your service or product. Then use those most searched for keywords in everything from naming your business, to naming you company website, to yes, even deciding words to use in print like on your company vehicle.
When a consumer has a wiring problem they need a professional to fix, would they type a vague word like "electrical" in their smart phone? Or would they type "electrician". The answer is the later. In fact they may type "Hertfordshire Electrician".
A quick search on google for what people most type when searching, shows ...
140 a month type "electrician hertfordshire" in google search. (with medium competitors)
more than twice as many 390 per month for "electrician watford". so if you served both areas, use both in your name.
"domestic electrician" 1,300 per month.
So depending on customers you are targeting, you may want to use for your company name, website and print on vehicle...
Hertfordshire-Watford Domestic Electrician
https://Hertfordshire-Watford-Domestic-Electricians.uk
(then have a SEO company set you company website up in local search engines like google maps. Then when someone in Hertfordshire type "Electricians" on their smart phone search, your website would be the first they would see.)
Know how many a month type in "electrical companies in hertfordshire", only 10.
Know how many a month type in "Maccas Electrician" a month? ZERO.
Summary: Know your targeted customers, find-out what they most search for, then use those words in every aspect of your business.