(09 Jun 2020, 3:43 pm)Adrian wrote Sorry for not responding sooner, but I've found the following for services 177/178 in the October '76 Sunderland District booklet.
Thanks Adrian . Yes this looks familiar to what I remember and this confirms what I thought about them being circular routes around Washington. For some reason I thought they'd went to Rickleton, Lambton and Ayton too. I think these services must have only ran on the Evenings and Sundays in the 90s as I remember the daytime minilink services being Orange, Blue and Green and numbered between 2 and 6 I think. Later on I believe the 2-6 were renumbered W1-W6 and the 177/8 were renumbered W7 and W8.
Thanks for again for taking the time to help out. Its very much appeciated!