Unfortunately I think you are correct to be concerned - at 2 you would expect him to be putting together 2 word phrases at least (mummy go/got car) etc and to have a larger vocabulary.
firstly - you will probably find once he hits 3 the professionals will stop being so laissez faire, as 3 is a bit of a watershed age - that the children who are just late talkers who will catch up without intervention usually do so by 36 months.
have just had a look at your other thread. google your local PCT, they will have contact details for SALT dept, and phone them yourself to find out situation re:waiting list. If they prove as unhelpful as HV has indicated, put in a complaint.
Phone up the local audiology department, and find out if you can self-refer. It's important you get a hearing test done, to rule out whether there's an obvious cause for any speech delay.
also look for information about ASD assessment in your area, and see what the usual procedure is. Im afraid when it comes to getting the right therapies etc for your child, you can only 100% rely on yourself to make the effort to make the phone calls and chase things up.
If you are at home in the day, some surestart centres run courses to help you help your child with language. they aren't as good as salt department run courses, but can be very helpful whilst on the waiting list. agree with advice on the other thread about looking at a private salt assessment unless NHS appointment is imminent.
SALT, however good quality, isn't a magic bullet. be prepared to put in a lot of work yourself. but also take comfort that once you are set on the right path as to what level your child is at and what to do next, there's a lot you can do for him.
useful books and websites:
1)you make the difference and/or it takes two to talk by Ayola Manolson. these are practical workbooks which give useful advice on helping your child communicate and talk
2)parent's guide to speech and language problems by debbie feit
3)baby talk by sally ward
www.hanen.org.uk
www.ican.org.uk
www.afasic.org.uk
www.teachmetotalk.com