"Having realised" is correct and commonly used in written English.
You can use it when you want to indicate that someone has come to a realization, understanding, or awareness before the main action or event in a sentence. Example: Having realised that she was running late, she quickly grabbed her keys and rushed out the door.
Having realised the collective dream and made it to America she learns that paradise is never quite what is promised.
Having realised I can now afford at least to glance at an estate agent's window - not in London, mind - I've been venturing out on a few viewings.
Having realised that prices can fall as well as rise and that houses are illiquid assets, many more people may opt for the greater flexibility of renting and hold their wealth in more diversified forms.
Having realised the benefits resulting from delivering on-line public services in the context of electronic government, administrations strive to extend the spectrum of services offered to citizens and enterprises, as well as to engage multiple communication channels in service delivery, in order to increase the target audience and, consequently, the service effectiveness.
Having realised that food is a very local business, the company will henceforth apply the bulk of its marketing and distribution resources to boosting its strongest health and personal-care brands in emerging markets, rather than trying to get Asians to put Hellman's mayonnaise on their salads.
Having realised that they can't beat the juggernaut from Redmond, they are devoting themselves instead to smaller markets, ones they have the strength to dominate behaving, in other words, like mini-Microsofts.Novell tried to compete head-on with Microsoft in desktop software, such as the word processor Word Perfect.
"Having realised this we have developed a new instrument technology around putting carbon-14 through camping gas.
Having realised that India was not going to talk about it now, the US apparently chose to endorse the Indian government's solar power goals.
Having realised this I regret ever neglecting my yoga practise and I will certainly be doing it more often again now, even if it's just in my front room with Spotify on and a few candles!
Having realised that the site was being misinterpreted as a feed-reader in the style of, say, Google Reader, founder Nick Halstead has now focused on the core goal of making feed reading and commenting as user-friendly and mass market as is humanly possible.
Having realised their mistake the Germans then steered for home.
