Home currency - wronly created in pound, values registered into euros. Can we just change it ?

Hello,

Last month, my accounting supplier in UK wrongly created our Quickbook online data base under Pound as a home currency.

We did not know nor notice that before we recorded our 5 months of accounting history.

Since our accountancy was in  €, on our previous software we registered all amount in euros.

So now I have amount in euros, showing they are pound.

I've registered an invoice of 1000 € that is appearing as 1000 £

I did not activated the multicurrency. So here my question, can I just change this option from Pound to Euros ?

my amount are already in euros so it will just change the sign of the currency right ?

Thanks for the help you can give me !

Marion