It could be that all that the proxy's operators can do is to porposely overload the channel, and thus at very slack times (early morning UK time = the middle of the night USA time) I got an occasional message through "when the pickets went for coffee". If one institution's server operators can do this, so can others; it would seem that we still need a way to let the user select another way than multipart to send those messages, to bypass this sort of nuisance blockading, if it is possible.