FLR (M) Visa

[Gezalenko]

My wife (British), 3 kids and myself (Australian) arrived in the UK on a holiday on July 27, 2018. 2 months into the holiday and my wife decided to stay. Our 3 year old has Tuberous Sclerosis and will be requiring brain surgery within the next few months so she wanted the support of family. So I applied for a FLR (M) in September 13, 2018. I clearly didn't read the guidance notes completely.
On October 17, 2018 I received a letter basically stating: 'Your application raises issues relating to the European Convention on Human Rights which are complex in nature. As such, it falls outside our normal service standards for deciding leave to remain applications. Please be assured that we will make a decision on your case as quickly as possible.'
From December 2018, I've contacted UKVI numerous times regarding my application. I have sent 3 letters to the PO Box in Sheffield, 1 to Croydon, 2 emails Home Office Complaints and 1 to the OISC with no return information. To my frustration I have been informed today (January 31, 2019) when I called UKVI for the 7th time that you cannot switch from a Visitors Visa to a FLR (M) visa.
Believe me, right know I feel bloody stupid! What are my options, if any?

[CR001]

Correct, you cannot switch to any visa category while in the UK as a visitor. HO's website states this very clearly too.

You should have applied for a spouse visa from home country.

Your only option MIGHT be to ask for or apply for FLR(FP) 10 year partner/parent route (4 x 2.5 year visas) and include medical evidence of the childs medical circumstances. These applications can take a very long time to be decided, sometimes in excess of a year.

Note also that IHS fees have increased to £400 per year from the previous £200 per year.

[Gezalenko]

Cheers CR001.
Okay cool, based on everything I've read NOW it looks I'll be going back to Australia to start again. The FLR (FP) as you mentioned can take very long and I'm desperate to start working as soon as possible (in the UK) so am I better off going back home and apply for a VAF 4A (spouse visa)?
Can I also ask, why send me that letter in October when it's clear I've made an incorrect visa application and why has it taken so long (still waiting) for a rejection notice to come back?
Sorry, just venting my frustration now.
So best option is to request my documents back, go home and apply for the correct visa and wait patiently for an outcome.

[CR001]

so am I better off going back home and apply for a VAF 4A (spouse visa)?

Usually the best advice we give.

Can I also ask, why send me that letter in October when it's clear I've made an incorrect visa application and why has it taken so long (still waiting) for a rejection notice to come back?

It is an automated response. Many applicants for various applications get the same letter.

So best option is to request my documents back, go home and apply for the correct visa and wait patiently for an outcome.

Up to you. You could wait to hear the outcome, which might be a refusal or you can withdraw and explain you will return to Aus and apply using the proper channels, assuming your partner meets the financial requirements etc. HO will likely return your passport to you at the airport though once you inform them of your departure date.