A bit optomistic these numbers.. Here's my guess of the current cost without lawyer.
Half day B1 language test €80
Travel to test centre €20
Acro €70
UK Apostile €130
Birth cert €13
Translation €100
Legalization Tribunale €32
Application cost €250
Bollo x2 €32
Postal costs €50

Total €777.
Things might go wrong too like failing the B1 or a document going out of date. Extra crime certificates from other countries.

It's an expensive business!, you have my sympathy,! Italian bureaucracy is always difficult but to pay such a lot of money for the privilege is doubly annoying! It's also expensive to obtain British citizenship the application fee is £1,300 before the costs of documentation, language test etc.

When they increased the price to Euro250 it is surprising they didnt go for a bigger increase.

Plus the cost of the new attestazione anagrafica and the new plastic brexit card. So many people's applications have recently been rejected due to not having the plastic card from the questura .... which isn't obligatory but many prefettura are being a pain in the backside about it. Those applying through marriage will have to add marriage certificate to that list too.

Costs also depend on how complicated your life has been so far, try getting a police record document from saudi arabia or a new birth certificate from south america somewhere!

Well Im obviously hopelessly out of date, it was much cheaper before Salvini came along!

I should have done it decades ago when it was cheap and easy and there was no queue ................... but I thought that I was safe once the dreaded permesso di soggiorno got eliminated in 2007 and I didn't have to renew that at the hated Questura.

Couldn't you get Irish citizenship? At least then you are an EU citizen.

Yes I can. I've got my dad's full birth certificate and everything. I was going to do it last year but the embassy website was closed to all online applications.
What I'm not sure about is this: if I re-register at the comune as being Irish and not British, do I start from scratch and lose my 30 years? To be honest I haven't made any enquiries about that.

You shouldn't lose anything because they don't de-register you. They just update their details in the same way as they do when you get a new ID card. Get you Irish citizenship + passport for future convenience when travelling, but as you will have you WA card, unless you run into difficulties, leave your residence be. (Unless you want to vote in local/EU elections )

No, it’s just updating details on file; it costs around 16€.

Thanks friends. That's good to know. I'll get myself an Irish passport. Sister has already got hers applying from the UK, the very same sister that voted for bloody Brexit. She wasn't amused when I called her a hypocrite.