I personally don't think there's anything wrong with what you're doing and how you're doing it. As long as you feel comfortable and strong, there's no need to slow it down too far. I've had my share of "hitting the wall and mileage drops" situation and, the way I made my mistake is, thought everything I'd done is down the drain and I'd have to start everything all over again. I would have been much better off to stick with it and carry on. Later I learnt that even Peter Snell had some bad patches and sometimes his mileage dropped in half. When you hit a bad patch, just jog nice and easily for a few days until the strength and urge comes back (and it will).
Another thing is that it really takes some time for most of us to adjust to a full cycle of the Lydiard program. I don't think any of the original bunch just jumped into the program and started running 100 miles a week with 10-milers in 5.5-minute pace. It took them several years and, considering they complete two full cycles a year (one for Cross Country and another for Track), it sometimes takes 5 or 6 cycles to really get the benefit from it. Naturally you might have some hard time adjusting in the early going. Times will come down generally. Earlier cycle, you may have to take easy jogging on shorter days instead of shorter faster runs as indicated in the program (remember, the long runs are the more important ingredient at this point as Kim Stevenson advised many times on this thread) and you're barely surviving on the third or even fourth day to have another long run (90 minutes or more). By the following year (second or third cycle), you may be running an hour in between and feel quite strong. By the second year you might be cruising those shorter runs and even try out to do "tempo runs" or "time trials" on those days.
Times will come down generally but the rate depends on the individual. For some people it may not come down as quickly at all. Remember, though, some people tend to do those long runs quite slow, others do them quite fast, and they don't seem to have clear indication of what their final times might be. The important thing, for base building phase, is to have those long runs in--if you can handle faster aerobic pace, great. If not, just chug along. After several cycles, you should be able to find out your own personal pattern to the program.