I would recommend selling it just locally. No postage - meet up and exchange toy for cash. If the buyer is someone you already know then perhaps they can come to you or you can come to them or meet somewhere else that's mutually convenient. If the buyer isn't someone you know well then arrange to meet in public, put the toy in a box and tape it up well and exchange for cash.
Considering how difficult this toy is to obtain I am sure that you will find someone who'll buy your Megatron.
I know of another TF collector who just lives one postcode away from me who's expressed interest in buying my PC MP36. Not sure what I'll do with my spare MP35 from PC () but considering that it's not a prohibited toy then I would put it for sale on my regular open thread and let anyone from anywhere have the equal opportunity to buy it.
That is IF I ever get these toys. I've started to resign myself to the possibility that I will never see my outstanding PC preorders and ride a significant financial loss.![]()