What you need is "UK AirspaceAVOID".
It shows your position on a moving map, shows all the current and up to date airspace, NOTAMs as well as airfields.
It warns you if you're about to enter an airpspace, highlights the border and gives you the appropriate frequency to call for entry.
It's tell you your current position relative to an aviation object, making it easy to report your position to ATC, and gives you the frequency for hte airspace that you're in at present.
It's approved by NATS and is totally free and constantly updated in the UK.
Search for "UK AirspaceAVOID" in the Google Play store.