No, 20th Century basing of British Army units was very rarely anything to do with where they were (nominally at least) raised. The post WW2 Royal Hampshires, for example, could be based in Catterick, Paderborn, Belfast or Belize almost entirely at random. Their Regimental HQ would still be local (usually in a barracks or castle within the county they were named for - the Royal Hamps were headquartered in Winchester for example) but the regular Army battalions of the regiment were part of the Arms Plot and moved to wherever the Army needed them.
The amalgamations through the years have generally been between neighbouring/local regiments (the RGBW was an amalgamation of the Glostershire Regiment and the Duke of Edinburgh's Regiment (Berkshire and Wiltshire) for example) or between regiments in the same role (The Light Infantry came about from an amalgamation of the King's Own Yorkshire, Somerset and Cornwall, King's Shropshire and Durham Light Infantry regiments). Well recruited regiments usually had more chance of being kept independant than regiments that were undermanned while other regiments had powerful backers on the General Staff or among Royalty - the Black Mafia was infamous for looking after the Royal Green Jackets after they were formed from the Green Jackets, KRRC and Rifle Brigade while the Guards have their Royal protectors.