Silicon Express
Silicon Express were based in Rothley, Leicestershire and produced the following QL hardware:
- Silicon Express Insider - a small disk interface
They also offered a 512K expanderam and a disk drive.
They also supplied one of the internal 512K memory upgrades at a cost of £150 (although the stop press on their September 1985 QL User advert said £199!)- this appears to have been a version whereby they replaced the QL's RAM chips, providing a total of 512K only, rather than the 640K which you could obtain using other 512K RAM upgrades.
Oddly the internal 512K memory upgrade was first advertised in QL User (September 1985), whereas Sinclair QL World (September 1985) advertised the 512K Memory Insider Board for £259.95.