Also be aware that if the server does get damaged then you will basically get very little back from any airline in terms of compensation, I think it is currently limited to 1131 SDRs which is approx. 1188 GBP. In theory this can be increased by paying a few, but it is not clear to how much it can be increased and how much it costs. So you would have to ask at check-in.

Depending on the type and configuration of the server then this could easily mean that a replacement could run into the 10s of thousands!

So you would need to check your/company travel insurance to see if it would cover such a situation. If not, then I would suggest to get it sent by courier.