Hello I'm new, help anyone please?

Hello everyone :) I have a 4 and a half year old son who just started reception 3 weeks ago, the teachers are amazing but they have had me in for a meeting about some of his behaviour.

Firstly he's a very social little boy, he will chat to any body, he's friendly, he will do anything i ask of him like get dressed or get this for me with no problems we go out for meals etc he sits very well, we go to the cinema to watch films, he's at a good normal learning level for a 4 year old, knowing letter and numbers, counting drawing, writing etc, is polite and has empthy and is very loving and wants to always join in and make friends, he doesnt have any repitive behaviours though he does know alot on certain subjects like dinosaurs or superheros but he's not obsessed with them, He has the odd normal 4 year old tantrums but nothing that's ever made me worry about anything. 

But they have said that in certain situations he misses 'social ques', he has bitten another child because they took a toy off him, he seems to become lost in the middle of a playgroud game, he often wonders into a diffrent area of the class room to play with toys (not always) he was scared of the hand dryers in the toilet, they say he does maintain eye contact but does often gaze past the person who is talking to him or looks away and is fussy about his food (always has been but he eats a good variety of foods). She said if she address the class for example 'everyone their coats' He looks confused and lost but if she directs it at him by using his name first he understands, there are lots of other little things but I am totally new to all of this and im trying to aleducafdle myself the best i can, im a little scared and nervous to say the least, they say that he needs a high level of care in school and needs to be assess, firstly how long will I have to wait for an assessment? I'm in Cheshire in the UK. Any advise or anything would be much appreciated! Please ask questions if you like I feel a little lost at the moment I have tried to write as much as I can but it's so hard to explain something!

Thank you so much for reading x