I was born 1970 so I didn't watch many shows in the 70s. But I remember catching some episodes in my teen years so when I discovered the DVDs I thought I watch the whole thing.
I usually have a soft spot for 70s shows as I do like the look and I remember things from that time like the cars or the clothes. Ultimately this was not that great for me. I liked the early seasons but the more I watched the more I noticed how I lost interest and let episodes just play in the background. There were some individual episode that were really good but others where I thought I watch a different show. At the beginning I liked the characters and their stories but there is little progression or development. I know that might be an unfair assessment as those things clearly were not important in 70s TV.
I do understand that this was an important show for British TV at the time, even controversial in it's portrayal of police work. I do get why people like it but as mentioned It just didn't hit home with me. I skipped the last couple of episodes.