Hi orangeanddemons:
Feeling the need to be a devil's advocate here but saying, first off, that I highly agree with Ihatespiders - this is your DC's homework and they should do it.
Sure provide materials, dig out scissors or tape, provide pencils & paper - maybe a snack - but you shouldn't be 'doing it'. You may need to give them a gentle push to get started - you may need to say no tv or video game until homework is done - or if the teacher hasn't explained what a story box is, you may need to search for an explanation or post a question on MN - but that's as far as your involvement should go.
Now the devil's advocate bit....
(context: my DDs are now in Y4 and Y6)
Our school rarely sends homework home - for DDs at most formal homework amounts to 10 - 15 minutes of effort (minimal at that) and is now due on a Thursday so doesn't have to be done at the weekend.
Homework is rarely levelled - all pupils do the same thing - and for my girls often is way too easy. The bulk of 'homework' is taken up by the school suggesting 20-30 minutes of reading a day - after Y1 books are not sent home (apparently too many lost books) so it's obligate on parents to supply reading material. There has never been any written homework. There is no marking of homework - just a tick (no initial even) in green by the teacher to acknowledge homework is done. There are no repurcussions for pupils who don't do homework.
Now over the years I've complained about lack of homework (I've also frequently posted about this here) and I've watched friends who's children went to the same nursery who've gone on to different primaries here in Birmingham and had homework like yours (build WW2 air-raid shelter, talk to grandparents about experience of WW2, learn 5 facts about our town, learn 10 facts about a Roman bath, etc....). Like you - they've complained and moaned about all the time taken from their weekends.
But - their kids all passed the 11+ with flying colours (some tutored, but most just did bond books) here and my DD1 just missed out (although will know for sure in March) she's roughly 10 points below last year's cut off.
So complain away all you like - but I feel I have a child working 1 year or more behind her counterparts all the way through and I can see the damage this is having to her life chances.
I would have far rather given up a few hours at a weekend to homework in primary than be in a situation now of dreading the mediocre senior school DD1 is now most likely doomed to be heading off to because she just didn't have the skill set to shine on the 11+.
DH and I are left wondering if we should have bankrupted ourselves to provide a tutor - but the King Edward schools (the state-funded grammar schools - entry based on highest scores) here all advised against tutoring for the exam.
We live in doubt and worry - and sincerely feel had DD1 had those funky homeworks that involved thinking, creativity and writing (instead of 10 ridiculously easy subtraction problems and a list of spelling words to memorize) she could be heading in a very different trajectory.
oh by the way local senior school only gets 45% of pupils to 5 A-C GCSE's. Most children graduate to be care assistants or work at homebase (at best) - it has never in it's history sent a child to a big name Uni.
So complain away - but perhaps think about the long-term benefits too....