Once the bailiff has been, can they return again?

Yes

The enforcement regulations place no limits in the number of times bailiffs can attend the enforcement address.

The only limitation is the fees that can be charged for attending.

For the enforcement of High Court writs, the bailiff can charge an Enforcement Stage fee up to two times for attending the enforcement address,^[1] regardless the number of additional times he attends

For the enforcement of all other debts, the bailiff can only charge the Enforcement Stage fee once no matter how many times he attends.^[2]

^{[1] Regulation 6(1) of the Taking Control of Goods (Fees) Regulations 2014
[2] Regulation 5(1)(b) of the Taking Control of Goods (Fees) Regulations 2014}