Capital allowances - new electrical supply & substation

Client is paying an electricity distributor a large sum to dig a new high-voltage cable to their premises (an additional supply).  They are also incurring expenditure building a substation (basically a transformer) to step-down the power to use for specialist plant in the building.

Electricity connection fee - could I get away with P&L treatment?  There is enduring benefit but none of the equipment is owned by client.

Electrical substation - not integral features (as not part of the building).  Possible enclosure which might be a structure so no CAs.  Transformer itself - P&M at 20% CAs?

Thoughts welcome!