I'm wondering is there a consensus as to what time it would be good to allow after the mother stops feeding the litter, before doing the puppies' first vaccinations?

How long is a piece of string

Titre testing is one option

That's why I asked whether there is a consensus.

For example, there is a consensus that vaccination against rabies provides immunity for at least 3 years, and vaccination against lepto provides immunity which doesn't exceed 1 year.

Is there a similar consensus as to the duration of immunity from mother's milk? (say the mother herself had her vaccinations up to date)

As ann says its  variable for each pup  but if u look at articles by
Ron  Shultz and jean dodds on the subject it may help u make a choice.   They have done studies on this and all aspects of vaccination  .

Mum's immunity, provided the puppies took her first milk (colostrum) should last for the first 5 weeks, after which time it gradually drops off.       It's 'normally' assumed that by 8 weeks, external vaccination can be given, and should 'take'.   We left our puppies to 10 weeks before having their first vaccination.  However, as has been said, not all puppies are the same - I knew a breeder in Canada who'd titre test each puppy before starting vaccination but for me, that could represent quite an outlay, cost-wise.   So as said we externally vaccinated from 10 weeks.   And none of our puppies went down with one of the sometimes fatal dog diseases.

After the first puppy set is completed, we booster 12 months on and then go to a 3-yearly booster routine, apart from Lepto which as I understand it, dips over a 12 month period and should be boostered annually.  Others will disagree, but this is what works, for me.   Oh and I drop all boosters by around age 7 upwards.   But I don't kennel my now two - boarding kennels may/will need this to be done and the dog's boosters up to date before being boarded.

Again going by what has worked for me, over the years.

A study of Titre test results gainsays the 5/8 weeks, most maternal immunity lasts over 10 weeks( hence the vaccine manufacturers advising dogs over 10 weeks only needing 1 dose of vaccine)

There is no consensus at all - some maternal antibodies can wear off by 6 weeks of age, others not until 16 weeks of age.   It differs from dam to dam and depends on her own antibody levels as to what she passes on in the colostrum.  Moreover, it is different for each core disease - the maternal antibodies for distemper may have worn off whilst those for parvo are still effective, for eg. 

The WSAVA (World Small Animal Vet Asssociation) recommends the final vaccination is given at 16 weeks or later, because there are still many puppies with maternal antibodies before that.

In North America, the final vaccine is given at 16+ weeks, for the same reason.  I truly believe the UK fad of giving the last vaccination at 10 or 12 weeks is dangerous and there are puppies out there which are not immunised, getting by on herd immunity until their 1st booster at 1year. 

I vaccinate our pups at 9 weeks and at 16 weeks and I don't include lepto.

Thank you, the last litter I did 10 and 12 weeks, I will try the second vaccination at 16 weeks in my next litter. I don't like the idea of titre testing, mainly due to not wanting to put the puppy through stress of having its blood drawn. Given that recommendations such as 16 weeks do exist, I suppose they tested a number of puppies to arrive at the generalisation - that'll have to do I guess vaccinations is a difficult question in itself with so many disagreements among people.