I put a tissue round my bitch this morning as she has been enlarged for about a week. There was a small amount of blood which was a little greeny/red. Is this normal for the first day of the season? Also the last two seasons she has been bigger (in terms of vulva). Will it get slightly bigger more into the season?                        Thanks

Sounds like the start of her season.  they can lose the 'gunk' first.

If you're worried or it smells wrong I'd take her to the vets to be on the safe side.

My bitch swells more by the time she gets to 8-18 days and then slowly goes back down again. Sounds like day 1, but I have never experienced green before? maybe a quick phone call to the vet will do no harm :-)