I lost data earlier too, I'm in Essex, so did my mate on Orange, I then forced mine onto T-Mobile and got H+ back, I always had signal, I just lost the H when I was in the orange network.
I had no data for about 45 mins (on orange), then it was back. there was an outage like this for a short ammount of time a few weeks ago on Orange and I was affected (in Essex) - weird :/ maybe its hiccups in their systems cos I know they are doing some network upgrades (like HSPA+ and stuff).