The diode I ordered yesterday to do the mod on the TH-205E came this morning, but it is a bit big.
It looks as if I might have to use a thin wire link after all.
The diodes I ordered have a rating of 3A whereas the one specified by Kenwood - part number ERB83-004 - is rated at 2A. You can see an ERB83-004 which is used as a reverse polarity protection diode mounted vertically just to the left of where I hoped to put this one in. It is much smaller.
There is room for the big diode but it will not be easy to get a soldering iron bit in and trying to solder such heavy leads to the thin leftovers of the old one could result in more problems.
Back to the drawing board.