That was exactly what I meant before: the LPs are outdated in view of the new succession rules that will come into force with the Succession to the Crown Act 2013. Parliament should take the opportunity to repeal the LPs and pass legislation regulating royal titles and styles in line with Continental practice, i.e. restricting HRH status to the monarch's children and children of the heir apparent only. The monarch's consort and the heir apparent's consort could also be made princes or princesses in their own right and the title of Prince/ss of Wales for the heir apparent should also be enshrined in law in line with the titles of Prince of Orange in the Netherlands and Prince of Asturias in Spain. All other members of the Royal Family, including the remaining grandchildren of the monarch who are not born to the heir apparent, would be untitled, or else hold the titles or honorifics to which they would be entitled according to British peerage rules assuming their parents are peers.
This idea comes up periodically, and I have to say I don't think it actually makes sense to do.
First of all, you're claiming that the Continental royals are restricting the use of royal titles and styles... but that's not really true. There are 9 Continental Royal families; the Swedes, Belgians, and Liechtensteiners all grant the same royal titles and styles to the children of the younger sons of the monarch as they do to the heir (actually, the Swedes one up it, as both of the granddaughters of CG are born through female lines, yet both hold royal titles and styles). The Danes allow for the same royal titles but a lesser style (HH instead of HRH), while the Luxembourgers grant a lesser royal title but the same style (they're merely "of Nassau" instead of "of Luxembourg"). The Norwegian king only has one son, and the Spanish king and Prince of Monaco only have sisters. Which means that of the 9 Continental Royal families, the only one that is actually restricting the use of royal titles and styles are the Dutch. That's hardly a huge trend to follow.
Even if the Continentals were restricting the use of royal titles, it still doesn't make sense for the British to do so. I'm not saying that the system in place is perfect - there is sexism at play, and it's going to become a problem when there is a female heir apparent - but it makes sense for the BRF to have a larger family than the Continental Royals. QEII is the monarch of 16 realms and do more than 3,000 engagements a year (according to Bertie's numbers). In order to sustain these kinds of numbers and in order to really pay attention to the 15 realms that the BRF don't actively live in they need more active royals than the Dutch do.
That said, what would happen if Parliament decided to change who has royal titles and styles in Britain (because Parliament has nothing better to do). In stripping the non-direct line grandchildren of the monarch of their titles and styles they would be stripping 9 people of their titles (3 grandsons of George V and their 3 wives, 1 granddaughter of George V, and 2 granddaughters of Elizabeth II, excluding the Wessex children). Of the 6 grandchildren, 3 of them have spent their lives dedicated to the BRF, 2 of whom gave up the possibilities of having their own careers. Do we really need to respond to over 50 years of dedication to the BRF and Britain by going "yeah, okay, that's all fine and dandy, but we're stripping you of your titles." That leaves 3 other grandchildren who haven't served the BRF in a huge capacity, but 2 of them are still in their 20s and who knows what the future may or may not bring.
If the Queen were to issue LPs that granted titles to female line descendants then that would affect, at present, a grand total of 4 people, all of whom are adults, and none of whom seem to actually want royal titles. I am of the opinion that this needs to be addressed, but I don't think it needs to be addressed now - it makes absolutely no sense to grant the children of Princess Margaret or Princess Anne royal titles and styles at this point in their lives. It's something that should be addressed in the future, when a daughter of William or Georges' is pregnant with her first child.
Also, the title Prince of Wales is not a guarantee. It's something that has to be created for each individual heir apparent. The issue of whether or not a female heir apparent can hold it does need to be addressed, but given as there isn't a female heir apparent yet there's no need to rush to it. Likewise, the Duchy of Cornwall (which is actually more important than the Prince of Wales title, as it comes with more than just a fancy name).
He was born HRH Prince Philip of Greece and Denmark and confusion existed at court whether he still held those titles 
Sounds like the King was having a little snit over something his son-in-law had said or done.
