In-world and Select World menu horribly laggy

Ever since round about 0.14.0, every time I press the main menu play button, there is around 10-15sec of lag before the select world menu shows. When it does, this too is horribly laggy. The scrolling background only scrolls for a second at a time, before freezing for another 10-15sec. I cannot select any button, nor scroll through my list of worlds! In game, pressing the back button to bring up the menu has about 10sec of lag, as well as when pressing settings or quit game. I have tried switching between classic and pocket UI's, changing graphics settings (despite actual game running with little lag at max settings), to no avail. It happens with or without internet connection. This lag is also building up slowly on my relation's iPhone 5S.
I often get the "Minecraft - Pocket Edition is not responding" popup
Music plays without interuption in the background
To recreate, you'll know about it if you try to press menu buttons and it lags 😛
My device is a Vodafone Smart Ultra 6
Thanks, and sorry for the long-winded explanation!

UPDATE - I signed into XBOX live, and the problem seems to have resolved itself! I still have 5sec waits between pressing menu buttons, so that's still a little wierd, but the debilitating lag on the select world menu has disappeared