Do bailiffs have to tell me where and when my car will be auctioned?

Yes

Bailiffs must give a notice telling the debtor where the vehicle has been taken.^[1]

The bailiff must tell the debtor the date time and place the vehicle will be auctioned.^[2]

^{[1] Regulation 32(1)(c) of the Taking Control of Goods Regulations 2013
[2] Regulation 38 of the Taking Control of Goods Regulations 2013}