People who got Tier 2 ICT between april 2010 to april 2010, there is no restriction of 5 yrs. Visa can be extended beyond 5 years, after 10 yrs you can apply for long term residency.

I believe tier 2 ict between apr 2010 and 2011 named as tier 2 ict- established staff. It was called long term staff after rule change in apr 2011. To avoid any surprise, it is better to check with the agent who process the visa for your company.