The 2 weeks on/off was started by Dr Newson when she wrote GP guidance on prescribing HRT a few years ago.
In that guidance she says that women will 'find it easier' to do 2 weeks on/off - (ie a memory thing) so it's not a clinical decision and it's not what the leaflet says.
The leaflet in your pack of Utrogestan says 12 days per 28 days. However, many consultants (like mine) say that using it 12 days on a month (30 days ) is fine. So you choose the same DATE each month ( for example, the 1st.)
The 14 day dose per month (as described as an option the leaflet in the pack) is an option for women who find they have heavier bleeding and need another 2 days per month to keep the lining thinner.
I've used Utrogestan for over 10 years through a consultant (privately.) I've never ever done 2 weeks on/off.
I hope this makes it clearer and you feel more confident using it.
It's only a minefield because GPs follow the guide they were given (to help them!) but most do not have enough training on HRT to offer variations.
The vaginal use is off-licence (in the UK not but in Europe) so in theory your GP can't offer that, but some are happy to do so.