A judicial separation is not often encountered in England.
What it does is to free the parties from their duty to cohabit. That means that it prevents both of you at a later date from relying on desertion as a ground for divorce, since the parties have been relieved of their duty to cohabit.But hardly anyone relies on desertion as a ground for divorce anyway. The use of JS is most frequently used by people with religious or moral objections to divorce.
I asked my solicitor for advice as to a possible JS and was told that it was not possible to get a Clean Break, which is what I wanted at the time.
There is a possible alternative to a decree of JS and that is a Separation Agreement. This also prevents you from relying on desertion as a ground for divorce, for the same reasons. A separation agreement is not watertight but there is a very good chance that it would be upheld if made with proper legal advice.
It sounds to me that you are both very sensible people and it's good that you still care about each other. But everything you say suggests to me that you would be well advised to seek legal advice and not rely on wikivorce.
There's a lot of money involved here and if you screw it up you could regret it later. My inclination is to think that you are right - it's better to sort this out now.
But don't rely on me.