Certainly looks like the steering rack based on those pictures

 

Agreed, steering rack or the PAS unit/motor which sits above that area on top of the rack.

 

Would the whole rack need to be replaced or is there any other fix? Any idea of a cost on this as due to the age of the car it might not be worth doing.

Car is still running fine and there are no issues with the steering.

 

You could try some PAS stop leak. If it's the seal on the ram then it will at least help as long as it's not completely torn. Give the gator in your picture a good squeeze to see if it's full of oil.

There's a 3 different choices of rack that vary on price. Your looking at about £3-400 for a replacement inc fitting

 

I had a success using PAS stop leak, but it does take several weeks to stop the leak. It's worth risking £10 to save changing the rack.
If you try it, after a few weeks, wind the steering fully right hand down and pull the rack gaiter off the rack to drain out the oil (clean the area first with something like brake cleaner). Refit the gaiter, and hopefully the leak is stopped.

 

Will get some stop leak tomorrow. Cars not worth spending £300 on. Will it be ok to keep driving short distances for the time being providing I keep an eye on the power steering fluid level? Steering is working fine at the moment.

 

Keep it topped up and it won't be an issue