How would I know that there is a ban on my travel to the UK or any other country? Is there some means such as an endorsement in the passport or the like? I ask because my Tier 2 visa recently got refused due to an invalid document. I'm guessing my agent gave incorrect details, but in my refusal it only states an invalid document.
Every country has its own immigration rules and punitive measures. The commonwealth does not share immigration responsibilities. That said, other countries, commonwealth or not, may ask if you have ever been refused a visa before and why. And they can share information if so disposed. You will likely have to deal with that for most of your future travels and it may lead to refusals (not bans, unless you lie and are later found out to have been lying).