The Troubles were a pretty popular topic in this sub a few years ago for some reason. While you're waiting for responses here, you may be interested in these:

• Recommendations regarding The Troubles? - /u/missginj shares their bibliography

• What started the 'Troubles' in Northern Ireland? - /u/ChuckRagansBeard supplies some reading recommendations, as does /u/girlscout-cookies in the linked thread, Could anyone give me a brief, modern history of the conflicts between Ireland, Northern Ireland, and the UK?

The Troubles was a period of violence between two factions in Ireland, simply put. One side - the predominantly Catholic Republicans, who wanted a united Ireland - and the predominantly Protestant Loyalists/Unionists, who wanted Ireland to be part of the United Kingdom.

Because the Irish government was mainly dominated by Unionists, who were Protestant, this led to some discrimination against Catholics, predominantly in employment, rights, etc. Because of this, the Republicans began to push for equal rights between the two religions and groups, and to push for a unified Ireland away from British rule. This was around 1968 when it began.

In 1969, following a period of serious unrest and violence, the British Army was sent into Ireland. Initially, they were relatively well received, as they were a peacekeeping force. They were never sent into Ireland to discriminate in the favor of one side, though this inevitably did occur. A notable incident was Bloody Sunday, when British soldiers from the 1st Batallion, Parachute Regiment, opened fire on a peaceful demonstration that aimed to stop internment on the 30th of January, 1972. Internment refers to Operation Demetrius, a British Army operation that involved the mass arrest and imprisonment of 342 who people suspected of being involved with the Irish Republican Army without trial. They killed 14 people who were unarmed, leading to even further anti-Army and anti-British sentiment.

I assume you mean IRA bombings on British soil when you refer to actions against the government. There were several, in fact. on the 4th of February 1974, a bus carrying British personnel from the Royal Air Force and British Army and their families was bombed by the IRA, killing 12 people - 9 soldiers and 3 civilians.

On the 12th of October 1984, the Brighton hotel bombing occured. Margaret Thatcher, the United Kingdom's Prime Minister at the time, and her cabinet, were staying at the Brighton hotel. A bomb planted by the IRA was detonated, killing a Conservative MP and four others.

Another serious incident occured on the 15th of June 1996, when a car bomb was detonated in Manchester city centre. It failed to kill anyone fortunately, but did succeed in totally gutting Manchester's city centre, injuring 212.

This video shows the Manchester bombing from a Police helicopter.

Those were by no means the only attacks to occur on the mainland, but they were a few very significant ones.

The SAS was never directly attacked in Herefordshire. They were a relatively unknown unit until the Iranian Embassy Siege, and as such they were not a primary target. They were, however, counter-ambushed in Cappagh in 24th March 1990.

I hope this has been helpful, if you have any questions let me know.