Reduce Shower Pump Noise

Wonder if someone could help me reduce my new shower pumps noise coming from airing cupboard.

I have several/multiple options i am intending on putting in place if people could comment as to their suitability that would be great:

Salamander CT50 pump.

Already mounting on paving slab

1st Solution:
Put a seal around the airing cupboard door to help reduce the noise leak through the gaps around door

2ns Solution
Box in shower pump. Have had several worries about this namely manufaturer does not like it as they say pump needs air to cool, but IMO pump only runs for a max of 7-10min tops, surely if the box is big enough this should not be a problem?

3rd Solution, insulate box around pump to further reduce noise.

thank you all in advance

You may be surprised at how much noise is trasmitted through the gap around a door, so a seal would be A Very Good Idea.

Depending on the door construction, you may find that it carries the vibration by resonating - if so, then tacking a layer of underlay to the back of the door would have a very calming effect on it.

I recommend that you don't attempt any kind of boxing in of the pump - cooling is very important, as the manufacturer says, and if you tried any kind of warranty claim then they'd know that the ambient temperature was too high. And the last thing anyone wants is for a pump seal to let water by and cause damage below the airing cupboard.