How Not To Write, A Work Email

Today I received a work email explaining that work permit rules are changing in the UK. The email explained how the rules have changed for new work permits recipients the BBC wants to sponsor. That's fine. I already have a work permit and leave to remain. However, the email included the following:

"This will also apply to anyone currently here on a work permit, who needs to extend or change their leave to remain in the UK."

So does that apply to me or not? If there wasn't a comma there, this clearly would not apply to me and I wouldn't have to worry about trivial matters such as, say, deportation. However, because the person writing this chose to include that comma, the sentence is no longer grammatically correct and while this might seem pedantic for me to quibble about, we're talking about my ability to remain in the country. So yes, I pointed this out in my reply, apologized for being a pedant, but explained that I had to have that clarified.

One would think that email with such a clear legal impact would be carefully vetted. One, would, be, wrong.

Well, especially after the fiasco with HSMP, where they did try to invalidate currently-held residence permits. That said, the new rules will only affect you when/if you need a new visa.

(Actually I'd really be interested in looking at a UK English style guide, because I know they do things differently with punctuation and am not sure of the British comma rules. The above sentence seems clear to me even though I would not put a comma there, which makes me wonder if I've been exposed to that construction a lot since coming here.)
That looks pretty clear to me. No harm in getting clarification, I'm sure, but it really wouldn't have struck me as particularly ambiguous.

The comma used for emphasis is pretty common, whereas a three-item list wouldn't even make sense - surely "people who need to extend or change their leave" would automatically be part of the category "anyone currently here on a work permit"?
Obviously there is no real point in me offering my comment-based opinion as I do not possess any relevant knowledge of work permit legislation, however, here I am!

The comma shouldn't be there as the only way the sentence makes sense is without it and (from my own experience) it;s more likely the sentence is correct and the punctuation is in error than vice-versa. (I left the semi-colon in "it's" as a happy accident which proves my point)

As an equally frivolous side note: apparently my idiosyncratic comma usage used to be so distinctive an ex-boyfriend managed to identify me as the author of an anonymous piece in a newspaper. Ever since that day I have been very edgy about commas. Fact.
Turns out the comma was, in fact, useless, and I shall not be deported.

I am certain that some folks will be unhappy with this.