No entry stamp on visa?

I recently noticed (after comparing my partners UK visa to mine), that I do not have an entry stamp on my visa. My partner flew to London in September 2013 with a stop over in iceland and received a stamp directly on his visa, I flew to London in December 2013 with a stop over in Ireland. I got stamped for a temporary stay upon arrival to Ireland, but didn't go through customs upon arrival to London. I have no stamp that acknowledges my arrival to the UK, and am wondering if this will be a problem if I wish to travel outside of the country and return before my visa expired? It didn't seem to be a problem when I applied for NHS coverage, but I don't want to run into any issues...


Thanks!

Since u travelled from Ireland which is part of Common Travel Area and treated as domestic travel hence no entry stamp required.there is nothing to worry about