FTSE 100 index futures contracts

Hello, I am interested in trading ftse 100 index futures and so far have traded without problem with a uk spreadbetting provider. Now I am considering to open an account with us futures brokers. I checked on the internet and I found to my understanding that there are two different futures contracts for the ftse 100 index, one traded on cmegroup exchange and the other through lse or liffe. The barchart.com website shows two different contracts for the index with slightly different price: E-Mini FTSE 100 GBP December 2016 (UVZ16) and the other FTSE 100 December 2016 (XZ16). My question is: are there two different futures contracts for the ftse 100 index trading at different exchanges with slightly different prices at the same time? Also I learned through google that e-mini ftse 100 futures contract from cmegroup has very low volume that some brokers don't even list it. So if there are two different contracts can I trade ftse 100 futures from liffe through a us broker? I would appreciate an answer from someone who has traded ftse 100 futures with a us broker.

FTSE 100 index futures contracts