Flower, I disagree re RTF. It is human nature to take the easy option and confident/competant RTF is FAR more likely to result in ATC service or a non-standard request being granted than some muppet giving their life story for half an hour. Yes we all fluff our lines sometimes and a missing piece of information may result in an extra radio exchange, but nobody really minds that.
On the other hand the slow/life story scenario will be more likely to get ROCAS FIS (remain outside controlled airspace, Flight information service). Mabee not fair, but thats life.
Going IFR will not help you to get transit/direct track in itself, but picking an appropriate level may. Obviously not really an option in SE England, but possibly a help elsewhere in the UK.
I have sat next to ATCOs saying that they will not provide a service to tiddlers because they don't pay the wages, but (I hope) they are rare and most will help if they possibly can.