Need to do a visa exempt extension for my mother. She's staying in a hotel, and the manager confirmed that they've done the TM30 as required.(Online)

What I have forgotten, do you need a copy of the tambien baan and a signature/ copy ID of the owner from the residence, same as required with a TM30.

Or just the form for the extension, a photograph and the 1900B ?

For registered hotels you do not need a tabian baan.

10 minutes ago, jethro69 said:

She's staying in a hotel, and the manager confirmed that they've done the TM30 as required.(Online)

If they did a TM30 they should be able to provide her with screenshot of the TM30. 

She needs to provide that to immigration to obtain the 30 day extension. 

When I bid, a month ago,  for a thirty day extension of my visa exempt entry  I was asked to provide a copy of Tabien Bahn since I was living privately and not in a hotel. This despite having a 17 year retirement extension history from the same address and having had my wife submit TM30 shortly after entry. I satified the requirement by providing a copy of my Thai Driving License which has the address on the reverse.

Having not been asked for this before I determined  it's yet another 'add on'. What is actually required is Proof of Address in an acceptable form.