My DD had the same issues with sequencing Maths. At 8yo, she was at exactly the same stage as your DD. unfortunately, the primary did nothing to help her with this, and she left Y6 at exactly the same point. 
However... She is now in Y10, still in bottom Maths set, still struggling and WAY behind expected levels for age, BUT she is 'functional' in Maths.
She has had a LOT of extra help with her Maths at Secondary, to the point where she dropped MFL in Y7 so that the school could work on her Maths and English.
She is now, at 15, just working on NC lvl 4 work, so around 5 years delayed. BUT that means she is 'functional' in basic Mathematics.
I have found that the 'MyMaths' site that they do almost all of their homework on in Secondary really helped her.
She is working her socks off in Maths, as she is desperately trying to get a 'G' grade in her GCSE, as she wants to actually achieve a grade, rather than get a 'U'.
DD can now add, subtract, do basic multiplications (she still has issues with 6's, 7's and 8's), do basic division, do simple fraction work, do simple algebra, she can tell the time (finally), she can measure and weigh things, she can name all the shapes, she can work out areas of a square and rectangle.
It's not all doom and gloom, even if the primary REALLY fails your DD, like my DD's primary did.
My advice is try to get her into the Secondary with the best SEN dept. and hold out hopes that if my DD can get to a 'functional' stage in Maths despite finishing Y6 still on p-scales, then it's not impossible that your DD will.
Is your DD dyspraxic? Because that CAN interfere with learning Maths, because the sequencing thing doesn't happen in some people with dyspraxia.
My DD still really struggles with 2-part instructions. That does make Maths hard for them.