What do you see as a mobile offshore base?
The main difficulty is lack of crew and when the 3 FSS show up it’s going to get a lot worse. Also as the MCMVs decommission, they will be replaced by RFA crewed PSVs and/or OCVs. In simple terms, to activate everything that is either in the water, being purchased or being built the RFA needs to effectively double in size. There is no sign of any turbo charged recruitment and retention policy being implemented for the RFA. This needs to change ASAP.
The 3x FSS and 4X Tide setup looks great for the CSG and LRG(N) but EoS RN is going to be completely reliant on partners to provide replenishment at sea without the Waves. It’s simply not credible to operate a meaningful force EoS without one or two RFAs providing support. Forward basing does not solve this simple logistical necessity.
The Waves are now 20 years old, have not been worked hard and with plenty of hull life remaining a modest conversion to provide two more balanced logistics support ships would seem sensible. Something similar to what the RCN are doing with their new Protecteur Class. HNoMS Maud is another great example. However MV Asterix is probably closest to what the converted Waves could and should become.
The Waves are dimensionally larger than all of the vessels detailed above making them perfectly suited for conversion to Joint Support Ships.
As Argus is likely to decommission at the end of the decade the PCRS role could be split between the two Waves and with an OSD around 2040 any replacements only need to be considered after the Amphib replacement program in the 2030s is complete.