Q: why does my iphone not recognise my ipad in Bluetooth

They do not connect to each other.  This has never been a feature of iPod/ipad/iphone.

The exception is internet tethering, if provided by your carrier.

these are the bluetooth profiles supported by ios

iOS: Supported Bluetooth profiles - Apple Support

these are all the bluetooth profiles

http://en.wikipedia.org/wiki/List_of_Bluetooth_profiles

pretty sure not device in existence support all Bluetooth profiles there is

See this user supplied tip to understand Bluetooth connections. Bluetooth: Why can't I pair my iPhone or iPad with another iOS device or with my computer?