Nice choice the Rega. I guess if you have the money and the Audiolab has issues it's a good move. From my experience I'm not convinced that new gear sounds a lot better than the old stuff, if the old gear is decent and working correctly. I recently upgraded my speakers and found my 20 year old Arcam Alpha 9 amp didn't have enough grunt to play them at really loud levels, being 70 watt RMS @ 8 ohms. It kept cutting out. I demo'd a couple of newer more powerful amps (Yamaha A-S801 and a used Roksan Kandy K2), these did not sound as good as the Alpha 9, so I never bothered.
In the end I bought an Arcam FMJ A39 blind, as I like the Arcam sound. This amp is 120 watts RMS @ 8 ohms, it goes really loud and never misses a beat, it sounds fantastic, the clarity and power is superb. However at lower levels it is pretty hard to distinguish it from the Alpha 9. So with lesser speakers in an attached house, I have a feeling it could be a waste of money. The input selector switch was starting to play up on the Alpha 9, despite being replaced once, the part is now obsolete.
But as you say if the Audiolab has issues, I'm just not sure that some newer gear is better at the same spec, a different manufacturer will have a different sound though. I just bought into this What Hi-Fi nonsense and that technology has improved, when usually it is extra features with some amps, like built in DAC's, bluetooth etc, all of which can be added with other devices.
Nice Arcam Alpha CD player by the way. I would personally buy a DAC than replace that. I bought a used Arcam IRDAC and it's superb, can also take a USB input from my PC where all my CD's are stored in FLAC format. The IRDAC 2 also has a pretty good headphone amp feature too, which is useful. As long as the transport is working fine in the Alpha, but again newer players offer extra features, along with a better DAC. I find it hard to notice large differences in CD players I've heard. I've never heard anything over £500 though. Speakers made the biggest difference to my system.
Nice gear though, enjoy the Brio