Wacky locations on check-in

I've been playing with the checkin feature and have had some, erm, interesting results.

I'm in Northern Ireland. BK settings are private, trusted friends see exact address, friends see city.

If I checkin to my exact home address, it looks fine on my screen - but to friends, it shows up as a town over 20 miles away. This happens whether I use a label or not (although the label is not visible to friends due to the privacy settings).

If I use my postcode to checkin, it puts me in Germany.

And then it gets really interesting.

If I use latitude/longitude to checkin to my home address, it looks fine to me - but it tells my friends I'm in Berkeley, California. It's still telling *me* I'm in Northern Ireland...so I only know it's completely wrong for friends if I check with them.

If I check in at a particular location in my town, using the business name, friends can't see my checkins or posts. I've mentioned this before.

If I checkin at a different location my town (across the street from the one above), using a street address, it's visible to friends and shows the city. That's fine. Now, if I use my latitude and longitude for that location, it shows up to me as "town, business, UK" - but it's actually a different business, over half a mile away. And to my friends, it shows up as Palo Alto, USA...