18 month sleep regression

My daughter is approaching 18 months old, generally our sleep issues have been few and far between, mostly improving within a relatively short space of time. That is until December, particularly early January onwards we have hit what I can only attribute to the 18 month regression, yet it’s been far longer than 6 weeks and we have had consistently bad nights with only a scattering of good nights in between.

we have tried it all but we are finding she is waking up all the time throughout the night. Upset but requiring very little comfort, absolutely no obvious reason. We don’t have support readily available but this weekend when my mum visited, she too witnessed them and can see no clear reason.

we now only offer very limited comfort but it’s relentless. My husband and I work full time, we have a 4 year old but for months have now been up 5/6/7 times a night and we are broken. We don’t see an end in sight and I don’t know how to fix something we don’t have a clue about what’s causing it.

day time naps are great, around 2 hours from 12.30 - little one will often sleep really well after 5am until around 7/8 easily and bedtime is between 6.30pm to 7pm.

desperately hoping someone can offer a miracle solution or can identify something we can’t?

any advice appreciated from a very desperate mum.