In 2006, UKVI (previously UKBA, previously BIA, previously IND, etc) piloted a program of using a 3rd party contractor to interact with end-users who had questions. This was a favourable move for two reasons:
- Entry Clearance Officers (ECO's) are trained to make decisions and not to give advice, accordingly they do not have the consultative skills to get the needed information from the end-user. Because of this they are usually WRONG.
- Direct interaction invites corruption and bribery.
The programme was made global in about 2008, and now consular staff are not allowed to engage the public directly as a source of immigration advice. The two issues I mentioned above were, to a large extent, solved by this. However, it left end-users in a deplorable state.
Consulates installed a phone system that 'ring fences' the ECO and his staff from contact. It's a complex maze (some say bordering on demented) of menu options that lead the end-user around in circles. The end-user will spend a half-hour or so navigating the phone menu and finally arrive back at square 1. Because of this, end-users who are 'veterans' of the process will tell you don't even TRY to call the consulate. People who suggest you call the British consulate haven't got a clue. You will only get frustrated and waste your time.
The 3rd party contractor operates a pay-by-the-minute scheme where you ask a question and receive an answer. However, what happens behind the scenes is that the contractor will look up the question on Google and find the appropriate text on UKVI's site and read it to you. If you didn't understand, or it did not answer your question, they will read it to you again. To be fair, they have a few scripts that they can read covering some of the corner cases.
What else can you do? You can look it up on Google and see what the internet has on it. This works in a lot of cases, but you need to be real sure to check the date of the article and the publisher's credentials. Also be sure to sync up whether the answer is for visa-nationals or non-visa-nationals. Respondents tend to leave out lots of relevant information and when you read something like "We had no problems at all", there is usually something missing or it took place in a different legislative era than today's.
So where can you get authoritative advice? two places: from a member of the Law Society (i.e., UK solicitor) or an accredited practitioner (i.e., reguated adviser). In the majority of cases, a single telephone consultation can clear things up. The usual cost is between 50 and 125 pounds. Yes, it costs. But it is the only avenue to get absolute authoritative advice on an end-user's circumstances. Good advice can save you money because application fees are not refundable if you are refused. This is the answer to the OP's question: solicitor or regulated adviser.
Just like anything else, there are good ones and bad ones. It's foolish to take a recommendation from somebody you do not know who uses a forum; in many cases it's the solicitor/adviser using a sock-puppet to promote himself. So get a recommendation from somebody you know and trust. I would not give one here on SO because it may be interpreted as pimping out a buddy for a commission (lots of that goes on also).
If you don't know anybody, then you can search the Law Society's site for a solicitor or, the OISC site for an adviser. Advisers are mostly just as competent (sometimes more competent) as solicitors and significantly cheaper.