Don't know why it shouldn't be possible....3-4 weeks would sound about right.....
But a friend of mine recently converted his IR at Bournemouth and it took about a month. It boiled down to about 1 hour per day, 10 in the Sim and 7 or so in the aircraft. Not sure why it took so long, he couldn't understand it either, and seeing as he was paying for digs in Bournemouth wasn't too chuffed about it.
They only fly monday to friday apparently, which seems terribly British
Had it been in the states, it could have been bashed out in three days.....but there you go