Constructive notice ill be satisfied if the purchaser of the land has made the necessary checks during the process of title conveyance.
Whilst actual notice is concerned with whether the purchaser was informed of the equitable interest, constructive notice is concerned with whether the purchaser made the relevant checks to find the necessary equitable interest.
The doctrine of constructive notice will place a burden on the purchaser to make sure that they have acted in an adequate manner to ensure that 2 major questions in purchasing title are satisfied:
Does the vendor have good title (are they the actual owners of the land?).
Are there any third party interests which may bind the purchaser?
The purchaser is under a burden to act wisely and take relevant legal advice in doing so to ensure they have adequate information regarding legal interests.