Certificate of Entitlement of Right of Abode HELP PLEASE !!

Just realised my Australian Passport with Right of Abode in the UK has to be renewed. I've planned to travel back to Australia early next year for Mum's 95th birthday ! As I need a 6 month passport validity traveling via Singapore, need to renew it now even though it doesn't expire until July.....
Just discovered that getting a new Cert. of Entitlement of R of A for a new passport is more complicated now and I have to start from the beginning ! It could take 6 months to obtain I've been told !! I've lived in the UK for a long time, and yes I should have got a British Passport before, but never thought it necessary (until now)

I don't want to take the risk of not getting it back in time and missing my poor old Mum's birthday, not to mention losing my expensive flight costs - hence, only solution would be showing my expired Passport with the Cert of Right of Abode with by renewed passport when I re-enter. This is something I did as a matter of course admittedly some time ago - but it was accepted no problem. ok now things are tougher, but has anyone had any experience of this lately and what treatment I should expect from the border control.
Thinking I could enter on a tourist visa, if things got messy ?! Any advice welcomed !
thank you

Apply for a British passport if you are British.

I would if I had enough time - that is the problem !

You should hv no problem travelling from & to the UK if u carried your expired ROA stamp (in the old passport) with you.
We hv had to do this recently.
Yes, I too just realised how expensive the cost has gone up by & also the long waiting period which is not practical.
Good Luck. If in doubt, I suggest you contact UK Border at the airport.

Anyway, can't do much else with the time available !
thanks !