If you are coming and going, immigration may try to give you a hard time in case they suspect you are trying to work or to illegally emigrate. Pre planning will help. Take evidence with you of strong ties to the UK to prove you are going to come back here. I.e evidence of a job waiting if you have one, likewise of a mortgage, or anything else like that.
Also helps to take bank statements with decent funds in to show you can support yourself and that you wont be trying to get work out there, and airtickets back to the Uk at the end of your trip, even if they are open ended.