Changing from Self Employed to Employed

The company I have been working for on a one year renewable contract for the last 3 years has now offered me a permenant contract and from January 1st I will be PAYE - up until now we have submitted a tax return with my husband who is PAYE as the assessable spouse and paid my tax in a lump sum following assessment of our total income I contacted the tax office to advise them of this but they brushed me off with a "we are busy ring back in January when you are formally employed" Surely I need to have my tax credits in place for January 1st or I will be paying emergency tax? I looked on the revenue's website but the only form I could find was for starting a new job or returning to work after a long period of not working. Can anyone advise me of what I need to do to make sure all is in order. I want to make sure that we continue being jointly assessed as my husband earns 4 times as much as I do and it would cost us an extra 2000 euro in tax if they give us separate assessment, my understanding is that we can continue to benefit from the increased standard rate of tax up to 37,000 of my husband's income with the balance at the higher rate and my income will all be at the standard rate, is this correct

Thanks for any help

Whether you are jointly assessed or not should not be affected by your status as regards self assessment.
You will continue to be jointly assessed unless you elect otherwise.

The 37000 married person band at 20% applies when only one spouse is working or if the second spouse is earning less than 19000.
Otherwise 2 married people are pretty much in the same position as 2 single people as regards total tax paid.

Thanks! I think I just needed to have someone confirm what I thought