Delayed Tax Year Overview Affecting Mortgage

I submitted my self assessment at the end of January but my self assessment hasn’t been processed by HMRC. We have applied for a mortgage which requires the Tax Year Overview, which can’t be downloaded until HMRC process my self assessment. HMRC advised to raise a complaint, which I have done, but to date I haven’t heard from HMRC (advised I would hear within 2 working days). HMRC advised they are seeking to take one additional resource to deal with the backlog, but surely this can’t be to my detriment? Our house purchase is going to fall through if I can’t provide this to the lender ASAP. Has anyone experienced a similar issue?

Hi,
If a return is received online but not immediately, automatically processed, it's usually the result of an issue with some information provided on the return, that we then need to manually review.
While we can't provide an exact timescale for your return to be processed, we are working to finalise all unprocessed returns.
If you'd like to raise a complaint, though, you can do so by searching for Complain about HMRC
Thank you.