Andrews4050 with regard to your visit in Istanbul: The UK Foreign office is a little more positive. Again the bold is my high lights.
The Foreign and Commonwealth Office (FCO) advise against all travel to within 10 km of the border with Syria and to the city of Diyarbakir.
The FCO advise against all but essential travel to:
•the remaining areas of Sirnak, Mardin, Sanliurfa, Gaziantep, Diyarbakir, Kilis and Hatay provinces
•Siirt, Tunceli and Hakkari
Security force operations against the PKK and related groups are ongoing in the Sur district of Diyarbakir. The FCO advise against all travel to the city of Diyarbakir. Similar operations have taken place in Sirnak and Hakkari. You should take extreme care in these areas. See Safety and security
Over 2,500,000 British nationals visit Turkey every year. It’s generally safe to travel but you should take additional safety precautions. You should be alert to your surroundings and remain vigilant in crowded places popular with tourists.
The threat from terrorism remains high. Terrorist groups, including Kurdish groups, Daesh (formerly referred to as ISIL) and far left organisations, continue to plan and carry out attacks. Further attacks are likely. Terrorist groups, including Daesh and the Kurdistan Freedom Falcons (TAK), have publicly threatened to attack tourist sites in Turkey. You should take extra care in public places – particularly those visited by foreigners. Be vigilant, follow the advice of local security authorities, monitor media reports and keep up to date with this travel advice.
On 12 January 2016 there was a suicide bomb attack against tourists in Sultanahmet in Istanbul in which 10 people died. On 19 March 2016 a similar attack against tourists on Istiklal St in Istanbul killed 4 people.
On 17 February 2016 a large bomb attack near a military barracks on Eskisehir Road in Ankara killed 28 people. On 13 March 2016, a similar attack killed over 30 people at Kizilay Square in central Ankara.
On 27 April 2016, there was a suspected suicide bomb attack at Bursa Ulu Mosque. The bomber was killed and 7 people slightly injured.
On 1 May 2016 a bomb attack at the Central Police Station in Gaziantep killed two police officers and injured 23 others.
Attacks are likely to target the Turkish state, civilians and demonstrations. Nevertheless, it’s increasingly likely that some attacks will also target western interests and tourism, as they did in Istanbul on 12 January and 19 March 2016. To date most attacks in Turkey have taken place in the south and east of the country and in Ankara and Istanbul.
Turkish authorities have successfully disrupted attack planning in the recent past. The Turkish authorities have said that security has been tightened in response to recent attacks. Nevertheless, further attacks are likely, could be indiscriminate and may target or affect places visited by foreigners.