The more I read on this, the more I see lots of general answers that either point to Testnet Ether donations, claim they have no difficulty in mining a ton of Testnet Ether (in no time at all) or suggest a private Blockchain is used.
I have found a great Testnet Ether 'donation' site at: Ethereum Ropsten Faucet but I really wish to mine using the public Testnet (rather than a private Blockchain) to ensure a 'as close to reality' simulation as possible.
Expecting life to be simple, I have downloaded the Ethereum Wallet which is connected and fully synced with Testnet and I have enabled mining (little pickaxe showing) and nothing has occurred after a few hours...
From what I have read, I was under the impression I completed these steps and I would see Testnet Ether flowing in, but alas no.
I also don't mind using Geth CLI if that's simpler and more visible but I can't find specific instructions on how to do this.
If someone can point me at a decent modern guide (or write one) that clearly communicates the dos and don'ts then I'd be delighted to complete the steps, create a video and get it live to help others out.