There is not a datasheet for the internal 24MHz Cortex M-3 processor that is embedded in the BLE device.
If I wanted information on the likes of timers, adc's etc where will I find this information?
Formal documentation is limited to the Datasheet for the part, and the Deoxygen HTML output inside of the SDK.
There are many, many posts here in the forum for each, even categories setup to organize the threads (look to the left margin of each page for the category assignments). Those, and the example code in the SDK are how most users familiarize themselves with things like timers and peripherals.