So the Electoral Commission recommend a "No pro" on Wendy Alexander because
"In respect of a possible offence under section 56, the Commission has concluded that, while Wendy Alexander did not take all reasonable steps in seeking to comply with the relevant legislation, she did take significant steps. Having considered all the circumstances, the Commission has decided that it is not appropriate or in the public interest to report this matter to the Procurator Fiscal.
In respect of possible offences under section 61, the Commission has concluded that there is not sufficient evidence to establish that an offence has been committed. The Commission has therefore decided that it is not appropriate to report this matter to the Procurator Fiscal."
Section 56 provides
"56 Acceptance or return of donations: general
(1) Where—
(a) a donation is received by a registered party, and
(b) it is not immediately decided that the party should (for whatever reason) refuse the donation,
all reasonable steps must be taken forthwith by or on behalf of the party to verify (or, so far as any of the following is not apparent, ascertain) the identity of the donor, whether he is a permissible donor, and (if that appears to be the case) all such details in respect of him as are required by virtue of paragraph 2 of Schedule 6 to be given in respect of the donor of a recordable donation.
(2) If a registered party receives a donation which it is prohibited from accepting by virtue of section 54(1), or which it is decided that the party should for any other reason refuse, then—
(a) unless the donation falls within section 54(1)(b), the donation, or a payment of an equivalent amount, must be sent back to the person who made the donation or any person appearing to be acting on his behalf,
(b) if the donation falls within that provision, the required steps (as defined by section 57(1)) must be taken in relation to the donation,
within the period of 30 days beginning with the date when the donation is received by the party.
(3) Where—
(a) subsection (2)(a) applies in relation to a donation, and
(b) the donation is not dealt with in accordance with that provision,
the party and the treasurer of the party are each guilty of an offence."
So if you don't take all reasonable steps "forthwith" it's an offence. The Commission say Alexander did not take all reasonable steps. So there is an offence. It does not - in its news release - address the temporal issue - where in other legislation "forthwith" means immediately, without delay (eg in the context of bankruptcy law).
Does the Commission have a policy on timing of the taking of reasonable steps (or even of the timing of significant steps)? And does this policy relate to general understandings of the word "forthwith" in law (given the appreciable delay in taking reasonable steps in relation to a letter from a private donor in an address furth of the UK with no indication it came from a company registered in Scotland - and which apparently formed the basis of the assumption that all about the donation was okay)? I think we should be told.
While the Commission might not be reporting matters to the Fiscal, will anyone else think it worthwhile?
I suggests that it's not over yet.

Comments
I must say that I'm relatively surprised that, in such a high profile case, the Electoral Commission decided not to refer the matter to the Fiscal, whose very job, after all, is to decide whether there's sufficient evidence of criminality, and whether it's in the public interest to prosecute.
The commission's findings include findings that the donation in question was 'impermissible' and that Wendy had not taken all reasonable steps to comply with the legislation. These two features combined would raise in many people's minds the presumption that the matter should be referred to the PF, rather than the reverse. Lawyers might call this a 'prima facie' case.
Some people might think what has happened is a whitewash, and may be sufficiently motivated to report it independently to the PF.
Before having too much sympathy for Wendy, one should remember that the rules which have been breached were introduced by the Labour Party in Scotland (including Wendy) deliberately and malevolently to prevent Sean Connery providing funds to the SNP.
I agree. I am waiting for someone to report it to the PF. Given that in the report the Commission acknowledge that an offence is committed but it is not in the public interest to take it further I was astonished that they took that decision. The PF decides what is or is not in the public interest to prosecute. The Commission acknowledge she breached the terms of s 56 and in my view the best person to decide on prosecution is the PF. My final line suggesting it was not the end of the matter was intended to suggest someone with a political motive (or an irate bystander) may report it to the PF him or herself. Perhaps - given recent public pronouncements - we should allow sharia law to govern the matter ;-)
Best wishes
Scott