Can bailiffs take cremation jewellery and wedding rings?

Yes

A bailiff has the authority to take control of goods owned by the debtor.^[1]

Enforcement regulations specify categories of goods exempt from enforcement.^[2][3]

^{[1] Paragraph 10 of Schedule 12 of the Tribunals Courts and Enforcement Act 2007.
[2] Regulation 4 of the Taking Control of Goods Regulations 2013
[3] Regulation 5 of the Taking Control of Goods Regulations 2013}