I have used TNT but the last time I tried (about a year ago) they would only do it if you had a trade account so unless the RFD at one end or the other can do this for you then its a non-starter. As for Parcel Farce, I would forget it, if it wasn't for ebay, they would have gone under years ago.
I have come to the conclusion that, unless you really are talking Northern Scotland to Southern England, it is less time and hassle to just get in your car and take it!
JC