"It's going to be extra basic pay, [and] extra shift allowances potentially, where those workers are not paid at the same level as the equivalent permanent employee,"

Most Agency Techs are already paid at a higher level than the equivalent permanent employee rate. Greater entitlement to holidays would always be pro-rata,(depending upon contract length), the main issue would be overtime. Most Agency Techs dont receive it, or only get flat rate.

In the present financial climate its hard to justify long term contract Agency tech's when an Employer could make a viable case for a permanent appointee who would cost less.

As a freelance Tech (who presumably has lower overheads) this will allow you to market your skills competitively against Agency Techs who will have to increase their overheads to comply with new legislation.

The downside is of course monthly pay to bring you in line with permanent employees.