Evidence for environmental and climatic change through Quaternary?

I'm struggling to find much in my readings

What types of evidence have you found so far?

I think things like pollen analysis, rocks, ice cores and Milankovic cycles may be good. Although I am worried if its irrelevant and also which is environmental and which is climatic.

Those are the types of things that I would've put too. I think Milankovitch cycles would be more of a mechanism than a piece of evidence for climatic change, though you could use the evidence for each cycle as a way to incorporate it better. Pollen analysis and rock types could provide evidence for both environmental and climatic change, since plants require different climatic and environmental conditions to survive, and rocks are deposited in different depositional environments. I'd say that ice cores would mostly provide evidence for climatic change, i.e. changes between glacial and interglacial periods.

That would be my take on it, at least

An others you can think of? Fossils, sea level change?

is this for A level or uni?

I did a module on quaternary environmental change in my last year of uni and i have still got some notes on it. but off the top of my head good areas to look into would be:
-glacial/periglacial landforms (evidence of glaciers or periglacial features on a landscape indicate a significant cooling period- you could also look into glacial retreat and advance evidence- which would tell you about if the climate was warming and cooling and how long it took to do so) (I might still have a pdf of a very good paper on glacial advance/retreat in new zealand- let me know if tat might be useful to you and it could PM it to you).
-tree rings (dendrochronology) good for more subtle climate change than what glaciers show
-river terrace sequences- in particular the sediments in the old river banks- there was a well documented study concerning the river terraces of the old and new river Thames if i remember correctly
-cave/lake sediments
-animal bones- e.g. evidence of hippo's and hyenas in southern england would suggest a much warmer climate than present- again looking at how long they were there can indicate how long that warm period lasted for.

hope that helps- quaternary environmental change is a bit interest of mine (especially glacial/periglacial stuff) as well as being one of my favourite modules at uni, so i'm happy to help further if needed

It's a 1500 word essay and i'm struggling how much and what evidence to pick

what is the actual title of the essay?

i would try and look up examples of each of the things i (and other people) have suggested in this tread. if you for example search something like 'Quaternary environmental change tree rings' in google scholar loads of papers will come up for this- read the abstract, introduction and discussion of these and use each of the things i suggested as evidence of quaternary environmental and climatic change. I should be around for a bit from 5pm tomorrow if you need any more help of if you want me to suggest some papers to read for you
just to confirm though- this is for university level right?

Is sea-level change also relevant?

i think so yes, as long as you are not talking about isostatic sea level change (that could link due to the isostatic rebound after glaciers melted but i wouldn't go into that as its a vague link) but in terms of sea level rising (or falling) due to glaciers melting (or growing) then yes that could work. e.g. sea level was lower during last ice age allowing Britain to be connected to mainland Europe and for part of the north sea to be dry land.