if I were you I would keep an eye on the interest rates as the Bank of England (BoE) is meant to be dropping them in Feb in order to try and head off a recession. No point in getting a 'mortgage in principle' until the rates have steadied for a bit as it will make a big difference to what you can afford to buy.
whatever you do make sure you get a FIXED RATE mortgage and NOT a tracker rate as this will fluctuate from month to month following the BoE's rates.
You will need to pay stamp duty on your property if it costs more than �120,000. (see below for thresholds:
Up to �120,000 - nil
�120,001 to �250,000 - 1% of property value
�250,001 to �500,000 - 3%
More than �500,000 - 4%
solictors fees are around �400-500 pounds but vary. you should pay for a homebuyers survey which will tell you if anything is wrong with your property (go for the best one you can afford as there are several different types - the more expensive the more info they will tell you). expect to pay around �300 for a farily decent survey.
you will not have to pay estate agent fees as these are always paid by the seller of a property and not the buyer.
searches are really cheap (can't remember how much but about �30 for each one).
hope this helps and good luck, but bear in mind what jake-the-peg and I have said about the current market!