In my case work started about 6 months after Gigaclear said the project would go ahead. I was finally connected just over a year after that.
Roadworks where shown on roadworks.org The first digging and cable laying contractor did not do a good job, and some of the work had to be redone as the trench filling had not been compressed properly before tarmac was laid. Gigaclear had to find a replacement contractor.
There was an issue about the siting of the first cabinet. It is on what you might describe as a wide verge which is actually private land rather than being part of the highway. A wayleave from the land owner had to be sought.
About 6 months after work started Gigaclear had connected a local school where they held a promotional demonstration, and had information about things like Vonage VOIP and Vodafome Sure Signal. I took my laptop and was able to run speed tests. I was able to talk to the Project Engineer and discuss where the cable to my house would be laid. I sent him emails about landowners afterwards. To my surprise a 2nd cabinet was installed near where I live. It was delivered late to Gigaclear which lead to a delay in my service.
I hope that gives you some idea as to what to expect.