RootsChat.Com

This doesn't answer your question, but for the record, the CWGC site has a page explaining some of the abbreviations in their documents (scroll down), including those you can get from most casualty details pages:
https://www.cwgc.org/find-records/about-our-records/glossary

I think there used to be a link to this on each details page, but it's no longer there. The URL implies it should be mentioned on the About our Records page off Find Records, but it's not there either. I've been looking on the Wayback Machine, but so far can't see when it went.

Having said all that, CH isn't there, but my recollection is that the list was once longer.

You could ask the CWGC what CH means, and incidentally prompt them to make this useful page more visible. For example, some of the abbreviations give a clue as to whether to look for one of their distinctive headstones or whether it's more likely to be a private family monument, some of which are now in a parlous state, or even removed entirely in cemeteries' reuse of graves.

Just for the record.

From Thornton's 1885 & 1887 Beckenham Directory (the earliest I have which goes house-by-house):
Allen Albert Harry, 49 Eden Road, Elmers End

Also there in 1889 Strong's Bromley; gone in 1891 Strong's.

For U.S. Labor Day. Ends today (apologies for the short notice), presumably 11:59p.m. Mountain Time, which I think is 6:59a.m. BST tomorrow, Wednesday 3rd.

Introduction
US Census
Canadian Census

The US census collection includes federal census records as well as some state and county census records and special census records. The Canadian collection includes national census records as well as some more specialised or location-specific census records. It says it has millions of additions since last year. Some of this may be free elsewhere at all times, so check before spending too much time on a particular set.

You need an account (free) but don't have to sign up for a free trial of the whole site. No payment details are taken on registration.

As always with free periods, save anything you find on your own device, as you'll need a sub to see it after the offer closes.

The British Genealogy Forum is there and has some recent traffic. Ancestry would have aquired it as part of Forces War Records which they bought a few years back and merged into Fold3.