If the HP manufacturer states that Type B is the prefered option, thats the route I’d take (without any debate😂) although its an odd preffered option as Type B are nornally reserved for if the Type is unknown. Anyway enough said on that.
On the PV side of the CU, you are best keeping seperate rather than sharing on the load side of a RCCB/RCD with other circuits such as your workshop. There is varying guidance on this from regulatory bodies, so much will depend on who installs it, but I do try to keep PV/HP etc circuits seperate, as a matter of good practice.
The choice of Type B is used in PV installations which has a power supply system (transformer) without simple seperation between the AC & DC side, however nearly all Inverters are transformerless these days anyway. The RCD will go on the output side of the inverter, as its best to design the supply circuit so an RCD isn’t required as above you don’t want have RCD that is shared with other circuits, hence my mention of RCBO’s yeterday. Rather than confuse the situation, perhapd we can talk more in depth on the PV side after your HP is mind sorted:-)
Using RCBOs do not necessarily require a split board however, due to the DC pressent on both the HP and PV, its recommended the circuits are divided to reduce the risk of tripping from DC lealage. Will work out later the ideal situation for the number of ways likely required and get back to you.
Page 8 “If Type A is selected for the heat pump circuit, the upstream RCD must be either Type A,
or Type F or Type B. ” You dont have an upstream RCD supplying a downstream RCD that supplies a HP Type A RCD e.g if your HP was supplied from the RCD in house CU and the HP was supplied from a Type A RCD, the House CU must be Type A, F or B so that an RCD won’t impair the operation of another (blinding)
MCB Types relate to their trip curves, where RCD’s tripping characteristics are in mA. They are two seperate things, that are combined in RCBO’s i.e Type C MCB will trip at 5 to 10 times the rated current and 30mA RCD will trip in 300ms at a fault current of 30mA.
Will have any comeback on the installer, not sure because there was an typo error in BS EN IEC 60335-2-40:2024+A11:2024, that was ammended in March 2025. However its worth contacting them with the manufacturers information questioning why they fitted a Type A on an inverter HP.