A good question that could help to create consistency in HU-EN translation.

First of all, telephely is a general term for any place of business other than the registered office, where certain conditions for doing business on a regular basis are met. This can be located either in the same town as the registered office or in another town or even country. If it is in another town or country, it is fióktelep (branch). See here: http://www.drlittner.hu/mit-jelent-a-telephely-es-a-fioktele...
So fióktelep is a special telephely, special in that it must be located in another town.

According to Hungarian laws, telephely is a permanent place of business, which should be registered in the Companies Register.

The term secondary was used in a FR-EN question and I was tempted to propose it in order to avoid the elusive term other. However, in many cases, a company's registered office is only an address they use for registration purposes and never conduct any actual business there other than service of documents. So secondary could be problematic in a case like that.

Quoting from a guideline available on gov.uk:
https://www.gov.uk/government/uploads/system/uploads/attachm...
Registration of an overseas company is only required when it has some degree of physical presence in the UK (such as a place of business or branch) through which it carries on business.

Another guideline published by Routledge, A Guide to The Companies Act 2006, also suggests that the pair place of business/branch is the same dichotomy we know as telephely/fióktelep in Hungary.
https://books.google.ro/books?id=HaYmUAGllvsC&printsec=front...
The place of business regime predated the Directive requirements, and continued to apply to places of business which are not branches. A 'place of business' encompassed both a presence less substantial than a branch and one where the central management and control of the company was in the UK.


So I assume place of business is a good term for telephely and I strongly recommend it (rather than business establishment) because it is the term used with the same meaning in the UK Companies Act. If you insist on using a more specific term, you could say permanent place of business.

--------------------------------------------------
Note added at 1 hr (2016-01-23 10:09:51 GMT)
--------------------------------------------------

I see your point, but please note the guideline I quoted from gov.uk. It DOES rule out registered office, because the guideline is addressed to overseas companies i.e. those with the registered office in another country. There's nothing to suggest that place of business includes registered office.

You could say other place of business if that helps to dissipate your concerns.

How about office or other fixed place of business, which is a US term? https://www.law.cornell.edu/cfr/text/26/1.864-7
The law of a foreign country shall not be controlling in determining whether a nonresident alien individual or a foreign corporation has an office or other fixed place of business.

Please read that whole section, because it does clarify what fixed place of business means in the US. It's practically the same thing as the definition of telephely in Hungarian laws.

SAMPLE MEMORANDUM OF THE LIMITED LIABILITY COMPANY
Memorandum of Association
We, the undersigned members, employing the sample memorandum1, establish the Memorandum of Association
of the following limited liability company as follows:

1. The corporate name, registered seat, business premises, branch office(s) of the Company
1.1. Corporate name of the Company:

Mondhatjátok, hogy hülye vagyok, de legalább következetesen.
Ha 15 évig elfogadták mindenhol csont nélkül, így fordítja a Bajzában a nagy Testvér is, nem fogom magam gyötörni.

--------------------------------------------------
Note added at 2837 nap (2023-10-30 12:50:22 GMT)
--------------------------------------------------

business premiseS