There are rubber and cork versions of the gaskets and they are shared with Peugeot, Volvo and DeLorean's.
For Volvo's they are a 260 engine type B28E and the gasket Volvo numbers are 1271483 & 1271484.
If you search under that car and engine, Autodoc have the gaskets in a number of different versions, Victor Reinz are good quality.
On my car the pressed rocker covers were quite flexible (and the rectangular washers missing) so I used Victor Reinz RTV sealant both sides to ensure no oil dripping on the inlet manifolds, this has been known to cause fires on Atmos.
For water pipes I got mine from Simon Auto in Germany. His sets use Turbo main hoses, but you aren't after a set.. There is a UK supplier
https://classicsiliconehoses.uk/our-products/ but they only want to sell sets, but their website shows you what you get, from memory its not as complete as Simon.
Cheers
Lee