Just to clear a few things up here as I think with a clearer head I can maybe put it a bit better and also I think some of the points I have made have been taken differently.
DS came home in tears saying he had verbally been invited to a party by X but didn't have an "envelope" (his description for an invitation)
I thought invitation may have been lost/misplaced by ds (5yr old boys are not the most reliable)
Went back to classroom to check tray etc and said to teacher why I was doing so. She said invitations were handed out last thursday with remainder handed out to absentees that day (tuesday). She had been given invititations for safe keeping and X handed them to friends under her supervision.
In an attempt at not being rude for non-replying (no invite, ds only knew some info and thought he had lost the invitation) I texted X's mum to say that DS thinks invited, understand may not be case, can you confirm. Reply from her saying not invited, numbers thing - no issue, fully understand and appreciate this and explained to ds accordingly. No problem
Another mum approaches me to try and arrange lifts etc and I say no invite so sorry can't help re lifts. She is shocked as X's mum had said whole class (17) were being invited (appreciate things change).
When speaking to ds he is adament that everyone got an invitation, no reason to doubt him but understand that his perception maybe wrong.
Throughout late afternoon contacted by 6 other parents regarding lifts. Thus showing that 7 out of 10 boys in class def invited, ds not, 1 still unsure (new boy started last week). This highlights to me that ds is only one out of original group of boys not invited.
My ds does not expected to be invited to parties, he sees them as a treat and something special to be included in. He has come home on several occasion saying that a particular child is having a party but only X number are going and he has been more than happy. He has become upset because there has been talk of the party within the group and he had (in his eyes) been invited.
I do not expect any of my children to automatically be invited to anything, but do become worried/upset when it appears that they are being left out and wonder if there is an issue or problem that could be underlying.
Child X will be invited to ds's party later in the year because as a family we have decided that the whole class will be invited (ds's first ever proper birthday party, and prob only for next few years) because we have the option to do this as party will be at home and the garden will accomodate everyone (hope it stays dry). In later years we will prob go for boys only and again he will be invited if it is poss to invite them all. If not then the party will done so ds invites two or three friends for tea and a treat/trip and no one child misses out.
Think that's it, once again thanks for all the comments