NOTAM
"A notice containing information concerning the establishment, condition or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel concerned with flight operations"
Essentially if the information in the AIP is wrong (e.g. AIP says there's an ILS but it's inop) then a NOTAM will be issued. Similarly if there's a restriction of flying or controlled airspace that is not in the AIP. You'll also get Unusual Aerial Activity such as air displays, PJE etc.
However obstructions are part of charting and will usually only end up as a NOTAM if they would affect an AIP entry, e.g. they affect an a/d and would alter the aerodrome chart or procedural charts that are in the AIP.
That is my understanding. Bear in mind that the amendment I pointed you at was a roll-up of several months worth. You'll notice gaps in the numbering series and it's quite possible that it was previously issued. Also bear in mind that there's no magical way of picking this stuff up. CAA are dependent on us letting them know. They're always happy to hear of useful new visual features or the demise of old ones (e.g. chalk hill figures that are no longer maintained and have grown over, demolished brickworks etc).
I understand the obstacles database is maintained by the Mil as they clearly have an interest. It was an error in that database that resulted in Stokenchurch Mast going missing a year or two ago. The current VFR Chart Editor is a lady called Jo Suter who is a cartographer with a PPL. She'll be happy to receive feedback, feedback form accessible from a link on the left of the page I linked to. It'll do no harm to remind them so it gets on to the next chart as a wind farm.
Hope this explanation helps.
Mike