Other Middle East and Africa Frequent Flyer Programs - BA to Egyptair C-class transfer at CAI question

Am looking at using up some BA miles this Easter for a trip to Egypt. The BA LHR-CAI flight arrives at 23:55 and I was thinking of booking an onward domestic flight on Egyptair for Luxor at 4:45AM on the same night. I have a few questions:

- Is this advisable, or does the terminal close and we could find ourselves chucked out? Any major difficulties in transferring from T1 >> T3 in the middle of the night?
- Is it worth shelling out an extra £20 per leg for business class tickets to get lounge usage? Is there a domestic lounge at T3 where we could "take refuge" and get some rest? Is it worthwile in terms of *A FF miles?

Any other advice appreciated!

Not sure about the transfer question.
The domestic lounge at T3 is tiny. It has comfortable seats and minimal food and drink. Not sure if the terminal closes at night but I wouldn't have thought so.

Terminal is open throughout the night, but check in may not be (for check in you need to pass through baggage security control first, anyway). Don't spend this extra GBP20, if the flight is operated with Embraer E-170 (Egyptair Express)- Business Class is a joke on these aircraft. On any other equipment types you will at least get decent seats (more or less similar to F on US domestic flights).

For intra-Terminal transfer, I would rather stick to taxi - buildings are located some 5-10km (don't remember by heart) apart.

The domestic lounge at CAI is very small. It has maybe 12 seats.

I don't have a photo of it but I do have a photo of the International Geniah Lounge. The area photographed is the about the same size as the Domestic Lounge - but with much nicer furnishings.

http://img36.imageshack.us/img36/5828/cairolounge.jpg (http://img36.imageshack.us/i/cairolounge.jpg/)

If the premium of sitting in a small room (note the tiny food offerings on the back right) appeals to you, then the premium is worth it. I personally don't think so.

Also to note - the lounges are dry and have no alcohol in them. . .