Topped up pressure on combi too much and water shot out of 2 pipes

Reduce the pressure in system with a radiator bleed key and a bucket. Obviously the nearest rad so you can see the level drop. Alternatively call a gas engineer. Good luck

You’ve forced the PRV to open at 3Bar. This valve is connected normally outside the property to allow discharge excessive pressure. Close the filling loop (stop putting water, and pressure in the system) give a full turn to the PVR until it click in close position, reduce pressure to 1.5 Bar on cold boiler. Furthermore, if the leaks comes from the pipe which is heading outside, and from the white pipe, I would personally call an engineer to check the connection under the boiler. The white pipe is there in purpose to discharge condensing water to the drain. All the best Tiziano