Wa `alaykum salaam wa rahmatullaah
Shaykh Haytham talked about this- but it is a issue that needs a LOT of explanation. The people differed regarding many astronomical matters- which thus lead to different timings. The best advise I take was from Shaykh Haytham, where he mentioned that one should fast at the earliest time- which comes in about 2:30 am (I think, since I am away from the UK at the moment). And to pray Fajar at the latest jamaa`ah time. This way you make sure you have made suhoor and you make sure that you have prayed Fajar on time.
With regards to `Ishaa', then really there is a time during the summer whereby the 'real' `Ishaa' time does not come in. There is a lot of discussions about this- but to keep it brief, if you CAN pray it late that is good... if not then try to pray about 1.5 hours after Maghrib. Again, that was the best advise that some of the people of knowledge in the UK have given. If there is a masjid nearby, then pray jamaa`ah with them.
But, with regards to fasting- then make sure you fast at the earliest time... as Suhoor is an individual act and not a communal act- thus it is not correct to follow the jamaa`ah in that... if they are wrong.
I just mentioned all of that in brief. If you wish to read more about it, you can read it here:
About Fasting times
http://www.islam21c.com/islamic-law/3087-the-correct-time-to-start-your-fast
About Fajar & `Ishaa' times in Summer
http://www.islam21c.com/islamic-law/166-summer-isha-a-fajr-prayer-times
Then I suggest you follow the one that is closed to your home...that is unless you live on one side of the Prime Meridian and the Masjid is on the other side! lol! Now THAT would be confusing!! lol!
As a Brother, you probably are spending your prayers in the Masjid so ask them for help. They would know best how to explain the discrepancy.
P.S Jen- The matter is not as easy as it may seem to be. I know you are trying to be helpful, but it will be well appreciated you do not give your opinions about Islaam. Thanks for trying to help.
Wassalaamu `alaykum