Changed the coolant temp switch too!
The fan on my mini is deffo the right way around blowing the air through the rad and out through the wing. The oil was changed only 3 days ago for good quality 20/50 and hasn't made any difference at all.
Thanks.
Regardless of which way round the fan is fitted, it will still blow through the rad, just not very efficiently if the wrong way round! Definitely worth checking.