Can a High court bailiff for unpaid utility CCJ Force entry?

No

Bailiffs executing a county court judgment CCJ or a writ of control, cannot enter private homes by breaking and entering.^[1]

Bailiffs can enter premises using reasonable force where the bailiff reasonably believes the debtor carries on a trade or business on the premises.^[2]

In short, bailiffs cannot enter by force any private home when executing a High Court writ, but he can enter any commercial premises the debtor is trading from.

The expression reasonable force is often interpreted by bailiffs to mean breaking and entering, but no such legislation exists giving that definition.

In any case, bailiffs are prohibited from using force of any kind against people.^[3]

^{[1] Paragraph 17 of Schedule 12 of the Tribunals Courts and Enforcement Act 2007.
[2] Paragraph 18a of Schedule 12 of the Tribunals Courts and Enforcement Act 2007.
[3] Paragraph 24(2) of Schedule 12 of the Tribunals Courts and Enforcement Act 2007.}