Come on Mac.....you can't pretend you don't know the answer to that
..however this is an area of real interest to me so I will indulge you.....
Theoretically, Any breach of covenant can be taken to court but the claimant has to prove that he has the right to seek to enforce and has suffered losses as a result of the breach. The latter, and the risk of costs, is why this matter rarely goes to court. Losses due to someone next door hanging out washing at the front of their house on a couple of occasions, would result in zero financial losses so one would be stupid to take that to court. Next door parking a van/ caravan on their drive where you can't even see it may not result in any losses either so may not be worth taking to court, however, for some it may annoy you enough to take a chance on seeking to get removed as long as you have money to burn since wheeled vehicles can be moved and then no longer breach the covenant.....in which case you then may win an injunction to stop it returning but since e breach is no longer occurring you risk losing in relation to costs. But all these are erratic/non-permanent breaches that result in minor actual losses but high costs so the risk of it costing money is very high. However, building another property MAY result in a permanent breach and reduction of one's property value and hence may or may not warrant taking the risk of a court case.
It would be up to the claimant to justify not having proceeded with the previous minor breach that resulted in minimal actual losses......and up to the Judge to decide if the issues are relevant and hence will impact the Judge's decision.....who knows????.....this is the chance you have to balance up when considering legal action.
There are lots of examples of breach of covenant that have gone to court and cost masses...eg Sandbanks windows case....but if you live in Sandbanks, you probably have enough cash to risk court and the values of properties are worth taking a risk for.....for the rest of us, it's a risk you may not want to take with your hard-earned readies!