Patent protection

Patents are territorial - they only protect you in the country within which you have a patent. If you already have an Australian patent, then your patent is a published document disclosing to the world what your invention is, therefore neither you, or anyone else, would not be able to obtain a patent in the UK because your Australian patent would be considered to be prior art. Now, of course, it is possible that someone in the UK may have filed a patent application before your Australian patent was published in which case they could possibly obtain their patent if the prosecution proves the invention, as claimed, to be patentable.

As Steven mentioned, patents are territorial. Accordingly, you do not need permission from an Australian patentee to commercialise the patented invention in an overseas country that is not Australia. This is on the condition that the patentee does not have a corresponding patent in that country of interest. However, you would not be able to obtain a patent in that country for the same invention because the disclosure in the Australian patent would be used against your patent application during examination.

It sounds like you are asking about trying to get IP coverage in the UK for the application you filed in Australia. Most countries allow a one year grace period to claim priority. So you would need to find out if you can still claim priority (within the year), and if you can, then hire an attorney in the UK (or EPO) etc., to file an application there for you. If you have passed the one year mark, then your Australian application would be considered a barring prior art.

Hope this helps!
Mary