Unless you have a specific need to house the sensor in the light fixture, using separate parts would likely produce a better result.
From my experience, many of the combo units are quite average quality.
As you found while removing the battery, heat is a killer. Going in should be quicker, but still be careful regarding heat accumulation.
Have the board cleaned of old solder. Use a hot iron and work fast. Hold, clamp, or have someone hold, a decent amount of metal mass against the battery...
I was always confused by usage of the term TDS. I'd never seen it unabbreviated, so thought it meant Trump Defender Syndrome.
All those rants with caps, bolding, underlining and personal insults make far better sense now.
https://9now.nine.com.au/60-minutes/vital-medical-supplies-sent-to-china-ppe-australia-hospital-shortages/94deca73-5640-4f08-913f-1ca1069b9473
There were companies here buying up as if they were private buyers, consolidating, then exporting.
Cruise operator under criminal investigation after 11 Ruby Princess passengers dead from virus
http://www.abc.net.au/news/2020-04-05/ruby-princess-cruise-coronavirus-deaths-investigated-nsw-police/12123212
There's a few people due for an arse-reaming over this. I hope the authorities follow...
Communism!
https://www.unilad.co.uk/news/officials-seize-nearly-one-million-medical-masks-and-gloves-hoarded-by-price-gougers
Better watch for excavators in your backyard. [emoji6]
https://www.nytimes.com/interactive/2020/04/02/us/coronavirus-social-distancing.html
Distance travelled doesn't entirely correlate to exposure, however it probably gives insight into the magnitude of effort being made.
Some more about cruise ships in Australia. Looks like they will be independently assessed, and if not in risk, moved on.
https://www.abc.net.au/7.30/what-can-be-done-with-the-thousands-of-passengers/12116348
We have them refusing to leave ports, and anchored on borders of International Waters, at locations around Australia. On the surface this poses risk of becoming an unreasonable burden on our medical system. The ships are foreign, as are the crew... "so go home".
Unfortunately if they set off...