Don't listen much do you.
You can't pursue this as it will only draw attention and all answers will be negative. If it's a small van it's not even an issue.The origninal developer has to enforce this, it has no connection with any local athourity or council.The developer doesn't like enforcement because it costs them time and money, and as time goes by is less and less likely to act.Some developers no longer exist, and in these circumsatnces it is unenforceable.In the worst case you will get a warning letter to begin with. Never admitt to anything, although it is likely that any neighbour seeking this action could take pictures.Any shed etc that you may have is purely as a hobbyist.
Running a business and parking a van are seperate issues.The LA may have some jurisdiction on the running a business in a residentail area.This would be more of a byelaw than a covenant.
Any house you buy will have exactly the same restrictions.If one or more of your new neighbours has a van knock and ask what they think (but don't ask someone who hasn't for fear of making trouble for yourself).
Never trust accountants.