The UK and Australian regions are classified as region B, thus all titles will be accessible.
Additionally, the Crunchyroll/Funimation titles will also be available since they fall under both A and B categories.
The other studios are categorized as regions B/free, so there should be no complications in that regard.
Regarding Sentai, they employ geolocking, which prevents Blu-ray players manufactured in other countries from functioning to avoid unauthorized imports. This restriction can be bypassed by adjusting the settings on the player to match the country of the Blu-ray's release. However, this does not appear to be a significant issue anymore, as it seems that this feature was removed from newer Blu-ray players some time ago. Furthermore, it remains unverified whether Sentai Blu-rays are now region-free, despite their indication of being Region A only.