There are no direct buses Praia da Rocha -Lisbon but with a change at Lisbon you can do the following from Praia da Rocha

Leave Praia da Rocha for Lisbon - arrive Fatima

0610 - 1155
0810 - 1425
1040 - 1625
1310 - 1830

There are no buses later than that.

One way fare €20.50

Details and booking on line at http://www.rede-expressos.pt or through a local agent. Sorry I don't know any local ticket agent and there is no listing for a ticket sales agent in Praia da Rocha. NB the rede-expressos website is in Portuguese only.

You might therefore need to go to the bus office in Portimao to make a reservation. There is a later bus from Portimao to Fatima through Lisbon at 1520

Thanks very much cubsor, really appreciate that. I think our best bet would be if we all went to portimao for the day. That way we could get them their tickets and put them on the bus and know that they have no change over to do. Mums over 70 and sister has mild learning disabilities, so the easier the better. I 've went straight ahead and booked them their hotel for 2nd- 5th. Hope there will be room on the bus for them. If wo go to Portimao early in the morning we should get tickets (I Hope).

Just to underline that they will have to change buses in Lisbon. There is no other way!