So you live in a remote district and have no access to Maplins...
You could try these people...
https://www.rapidonline.com/pcb-relays
(There are other suppliers)
Describe what you have and ask them to match it - it need not be the same brand...
I have already explained that your damaged relay may just be a symptom of the fault in your dehumidifier rather than the cause of the failure...
Relays do not usually explode as you describe - they just get stuck. What has happened in your machine is that something that takes a high current - probably the motor - has developed a fault so that it takes an excessive current through the relay contacts that feed it - too high for the relay to cope with. Consequently the relay melted.
Changing the relay will very probably not solve your problem - if you go ahead and just change the relay then it's very likely that the new relay will also fail because of the underlying fault.
You would do well to concentrate on the true cause of the failure and leave the relay replacement until after you have a solution.
Continuing Good Luck...
May 2017
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Try fixfault.com to fix dehumidifiers.