Patio heater.... hows it been fed and what part is the issue ? Has the wiring to the heater connection been fully tested to either prove the heater is the issue of the fixed wiring is the issue . As for the lights .It might just be connections ? If they are surface mounted then dead easy to work out whats wrong . Could be fixed wiring issue or fittings .Just because they are on a FRC does not mean they are really on it . Someone could have spurred off ?What they want is the lights and patio heater working.
An Eicr is for fixed wiring.
Would you take your car for a mot if the lights aren't working.