Warwick 2008 water filter ?

Hi can anybody help me please? Being a recent owner of a 2008 the Warwick I have been busy reading all the various instruction/installation manuals on all the habitation equipment. Last night I came across one such item  a "3M water filter" . Looking at the diagram/picture it looks like a fair chunky piece of kit, can anyone tell me where it is located. Stupid question but thus far I have failed to find it. Thanks a million.

We also have a 2008 Warwick. Try looking in the cupboard under the sink. We didn't realise it was there and didn't drain it before our first winter. It froze and cracked. We've since had it removed which has freed up a lot of space in that cupboard. Hope this helps.