We did actually manage to get our first passport for our child on the same day. We were applying for myself and husband also. If I remember correctly, we had to go back a few hours later. They told us ours were ready, but would have to post our our child's. We were due to fly out to Canada within a few days. I think we just struck gold with the person dealing with us. Whether it was the Christmas spirit, or he just took pity on us, he did break protocol and give it to us that day. I realize, this is not the norm, though.
I'm encouraged by the positive experiences of previous posters who have renewed from Canada.

Thanks BritinParis! Very useful information too. Now considering the one week fast track option!

But averages are meaningless if you are dealing with a statistical sample of one. In other words, it is no consolidation to know that 99.5% of passports are received without a problem if yours is the 1 in 200 that goes missing. It's the same reason I eventually decided against lasik surgery on my eyes!

I know we had to sign for them when they were sent back to us so there's some safety there.

Just as it's no consolation to know that nobody else lost theirs on the way home but you did.

BIP is right it's very quick applying from Canada and has been so for absolutely everyone I know. No post involved. Everything is couriered back. When I think of the hassle and uncertainty I perceive I would experience going in person in my limited time in the UK, or doing an in UK fast track post Application, I just find it hard to imagine why you'd do this. But that's me.

I have just done my daughters. They had a query about the person signing the paperwork, but even with needing extra information it took less than three weeks.

A bit off topic, but what is lasik surgery?

Using a laser to shave layers off your corneas to compensate for deficiencies in the lenses in your eyes.

The results for some people are very good, but whether the results are good or bad, they are rather permanent.

I came to the same conclusion.

I just received my daughter's first British child passport. Our supporting documents arrived in the UK on September 25th and the passport left Durham on the 29th and was received here in Vancouver on October 2nd. Sent via DHL both ways

I had laser eye surgery 2 years ago, but PRK rather than Lasik. My vision is better now than it was wearing glasses before. No guarantees, of course, although doing your homework and choosing a reputable surgeon who is a leader in the field helps increase your confidence in a positive outcome. I understand it's not for everyone though.