The old Borland compilers can be downloaded from community.borland.com. You don't get the manuals but the full working compilers are available. To find them, select Search and type "antique software| in the search box. If you know which compiler you want, type the full name of the compiler as well. For example, typing "antique software turbo pascal 1.0" will bring show that compiler as the first search result. The direct links for the old compilers are as follows:
(If the compiler won't run on the Apricot, it should still run on an IBM PC and compile code which will work on an Apricot).
Turbo Pascal 5.5 is also available and TASM is probably there somewhere.
*S - contact Sierra Systems (see Companies page )