I think I have identified Letitia but it's a complicated story.
I wanted to find Letitia on 1881 census (3 years before her marriage) and eventually found this which intrigued me so followed back re. census, etc.:
1881 - 13 St Edmunds Sq, Northampton St Giles
David Young 47 Farm Labourer born Tring, Hertfordshire
Jane Young 41 born Wendover, Buckinghamshire
Letitia H. Young 18 Shoe Machinist ditto
George B. Young 14 Shoe Rivetter ditto
Ann Butler 16 (a boarder) Shoe Machinist born Kingston on Thames
So, here is a Letitia H. of the right age, and a boarder named Butler (which may well be a red herring but possibly related to George Butler in some way).
I think that the enumerator may well have made an error with 1891 census and that 'Letty's' birthplace should read Wendover (Bucks) rather than Weedon (no Howe's in Weedon at all).
Rather than follow my tortuous route backwards I'll start with who I believe is Letitia's mother.
Surname is Pedel (but noted as all sorts including Piddle/Peadle/Peedle)
Jane Pedel bc.1840 Wendover, dau. of Joseph and Eleanor (can't find birth or baptism but on 1841/1851 census). Joseph Piddle married Eleanor Barnett 21/6/1821 Wendover (their earlier children baptised but not younger ones). I should mention here that there are a number of trees I've found on Ancestry who have muddled up 2 different Janes who were probably cousins. Another Jane Pedel was bc.1836 Wendover, dau. of a James and Ann - James Piddle married Ann Mead 19/7/1819 Wendover - who remained single and later lived with her brothers, the younger ones births showing mmn as Mead.
Jane Pedel bc.1840 had 3 illegitimate children:
Ellen Matilda How Pedel - birth Mar.1859 Wycombe
Catherine Ann How Pedel - birth Dec.1860 Wycombe
Letitia How Pedel - birth Sept.1863 Wycombe.
I then think (as Pedder) Jane married a Henry Bye 15/1/1868 Marylebone, London - she must have been heavily pregnant as a son George Bye birth Mar.1868 Wycombe - mmn Pedel.
Now to 1871 census: shown as surname Bye and living in Tring we have Jane's 3 illeg. girls - Ellen Bye 12, Annie Bye 10 and Letitia Bye 8. Ellen is shown as Head of the household with note shown (Parents gone to London). So a 12 year old in sole charge of 2 younger sisters!!!!
1871 Finchley we find: Henry Bye 49 born Cirencester, Glos., Jane Bye 28 born Wendover, Bucks. and George Bye 3 born Wendover.
On 25/11/1878 a widowed Jane Bye married a David Young in Northampton.
This then brings us to the 1881 census which started this post.
So, Jane's 3 illegitimate daughters born as Pedel all had 'How' as a middle name - one would presume that a Mr. How was their father. (census shows there were How's, Howe's and Howes living in Wendover). In 1871 they are shown as 'Bye' (surname of their mothers new husband), and in 1881 Letitia is now Letitia H. Young (surname of mothers second husband) and half-brother George Bye now shown as George B. Young.
As you can see, this sure is a complicated saga - why Letitia married as Letitia Howe (when her legal name was Letitia How(e) Pedel) I have no idea. Interesting to know who she named as father (if given as Howe this could identify who he was in Wendover) or she may have left the details blank.
Annette