Where is 'Allenby' located? Doing a quick Google search should give you some idea on whether the name is worth buying or not. If I do a search (Here in the States) for 'Allenby Law' I don't see much..
Looking at the results with a quick glance - This might be a name worth passing on. Normally, if we were to do a search for a worthwhile domain, we should see bunches of results right away. For example, if you Google the example above:
We see a load of great potential buyers right there on the first page. The more pages back we go and still see developed homepages, the better it is and more chances you have of finding a buyer. As for contacting them, the most common method is to do a whois on the domain or look around the web/website for a specific contact. You usually want to refrain from emailing "sales@" or "contact@" as these generally do not reach a decision maker. Look for them on social media (Twitter/LinkedIn) and try contacting them through there, look on the whois or across the website to see if you find someone specific that may at least be able to get your email to the proper person/department, call them..The method for reaching out is up to you, just remember you want to try and reach a decision maker, not some customer service representative who will likely just move your email into the trash bin. Hope this helps!