Clubs are a no go really as I work 4 on 4 off rolling over so I wouldn't be able to go for 4 weeks at a time. New bike?........ No go, no cash! Down hill routes? Live on the Essex coast so not many hills and it would just be cheating! Lose weight? I'm trying! Probably 1/2 stone to go. As for a coach, not even an option! How do you guys find interval training? Does it work? If so how often should it be done?
Intervals can be done in all kind of complex ways ... I like the Swedish 'Fartlek' method which involves using the terrain you have for intervals, like sprinting between lights, rest the next set, sprint the next etc. It can be between road signs, villages whatever as long as you have a periods of high balls-out activity followed by spinning recovery. Mix short efforts with more sustained.
Alternatively, ride with others or a riding buddy, you tend to increase your average work rates.
Turbo trainers are also good for interval training, I use an mp3 player and sprint a track, spin a track etc. A mix of tracks gives different intensities.