Hi folks sorry for the delay in posting.
We eventually got another carnet. It was very stressful . Lots of phone calls and e mails starting from Africa for two weeks. We had to scan all the docs sign and resend them.
Then silence from the RAC. Somehow they did not receive the docs. Diana had to fly back to the UK for a wedding.
We were given a price for the carne which was double the value of our vehicle. This was unacceptable especially with Egypt involved, fortunately we had an original valuation for our bank guarantee from last year. The RAC would only accept this from someone who knew the vehicle. Any modifications are irrelavant. Eventually they agreed to our valuation and then it was straight forward. Two weeks later and Diana returned back to Africa with the new carnet.
One thing to note is after much discussion they agreed we could have the new carnet start date the same date as the old carnet ended. They also dropped the request for the date and name of border we would cross.
We had to drop Egypt off the carnet due to cost and the political situation. However if we need to go through Egypt it is possible to buy an Egyptian carnet for one month or use a TIP.
Another problem, our bank guarantee was for two years and the bank will probably charge for the second year as well as us paying the insurance indemnity to
The RAC . We will keep you posted . All in all a pain and racket.

Sorry it took so long to get back to the forum, we've been flat out preparing to leave.
Anyway we eventually got our Carnet from ADAC in Germany. They were as courteous and efficient as you would expect but wouldn't move until the RAC agreed. At first the RAC refused so I sent the following email to the head of department Ms Lenthal,
"We were very disappointed to receive your decision concerning our application for a carnet and would ask you to reconsider on the following grounds;
- The RAC no longer offer the type of Carnet that we require ie a cash deposit carnet, the type that we have had from you for our previous two trips. There are a number of reasons for this. Firstly our vehicle is very old and has a low value, your insurer will only insure a minimum of £1750 where as on our last trip (2010) the RAC agreed a value of £1000 for our Land Rover. Secondly we have had two Carnets from the RAC in recent years and met all requirements upon return to Europe. Your insurer does not recognise this and offers no related reduction in costs although we are obviously a lower risk than others that they insure. Thirdly we may well not return to the UK for 13 or 14 months. Your insurer offers no reduction in premium to recognise this shorter period of a month or two for a carnet extension and we could be faced with total costs for insurance that amount to almost twice the value of our vehicle! I'm sure you agree that this is not an acceptable situation and the RAC do not appear to be offering the service that overland travellers require.
- You say in your reasons for refusal that "under the terms of the carnet convention the CPD is issued by the issuing club of the country where the vehicle is registered" and yet the ADAC in Germany is perfectly happy to issue us with a Carnet despite the vehicle being registered here in the UK and in fact cited several previous occasions where they have received a "non-objection" letter from E. McLissold at the RAC for some of your other customers.
- Finally I find it hard to accept that the cost or raising a Carnet here in the UK can be so different to that in Germany. To buy a Carnet from the RAC I will have to lay out £2029 (for a 1984 car) of which £1050 is refundable. A cost of almost £1000 or £2000 for 13 months. In Germany this would cost me €295 (£245) with a fully refundable deposit of €5000 or £490 for 13 months!! How can this be? Surely the RAC Carnet is not only for wealthy people?

If you can not or will not reconsider our application then could you please advise me of our legal rights in this situation?
In this supposedly free market across the EU how can the RAC restrict access of an EU citizen to an alternative product available elsewhere in this common market. Surely there isn't country based monopoly in this situation?"

Eventually Louise Campbell (customer service) agreed and we got our Carnet! Our travelling companions then emailed Louise and she allowed them to go to the ADAC as well. Oh and then we got a further €100 discount from Germany because we are members of the AA here!!

So, what to do. The Carnet system world wide is run under the auspices of
the FIA and the AIT. Get onto both their websites and complain that the RAC are not offering the service that overlanders need or want. This is the only place where pressure might make a difference. Breaking international agreements by printing your own carnet will only devalue the system and eventually we will all pay the price as its running costs increase or it is withdrawn altogether.