hi all, i have just signed up to this site, it is a super resource and i am looking for some advice please. i have a 13 month old cocker spaniel called henry who up till the last month has been a very sociable chap and very good mannered bar the usual chewing etc. 2 things have happened in the last month which i feel have changed his personality, firstly 3 weeks ago we went on holiday for 2 weeks, i didnt put him in kennels but got my friend, whom henry adores, to stay here at home with him, they got on well and henry didnt appear to miss me, although has got extremely territorial and barky then last sunday i was at a friends house who has a dog the same age and didnt realise thaqt her bitch was in heat and henry was trying to mount her constatly so i brought him home, since then he has been totally hyper and frisky and really aggresive when people approaching us out walking and even at the neighbours chilldren, in fact i dont rust him and cant let him off the lead at all, he is like a different dog and i'm at my wits end. i have considered neutering him but is he too old now, will it make a difference? i would love to show him and unfortunetly cant if hes neutered but would sacrifice that as i want my good natured boy back. can anyone please advise me ?