Hi, Nigel.
The reason you can't find the regulations for Committee Meetings in the Horizontal Law is because the Law does not regulate urbanisation committees. These committees are not a legal requirement. The Law requires for Communities to have a President, an Administrator and a Secretary but committees are not required. Therefore, creating a Committee is purely voluntary and it is up to the Community to decide when meetings will be held, if minutes will be kept or not and how to make the decisions of the committees known to other owners. if at all.
In some cases, these things are regulated in the by-laws (estatutos) but very frequently, as in your case, there is no regulation and the committes just organize themselves in whichever way is convenient.
Just remember that in a Community decisions have to be taken by an AGM or an EGM held in accordance with the legal requirements and voted by the required percentage of owners and coefficients. Therefore, Committees are generally there only to debate things, study proposals, get and consider fee quotes for services, and deal with emergency situations, etc. but legally these committees cannot make decisions, but only bring them to the consideration of the AGM or EGM, as the case may be. In emergency situations, the Horizontal Law authorizes the President to decide or urgent remedies (for example, the power goes out in the garage and stairways or there is flooding of common areas from one of the apartments) but a committee is not even mentioned in the Law. The Law provides for a Vice-President to act as President in the absence or inability of the President, but it is not a legal requirement for Communities to have a Vice-President.