T5 850 Oil Leak Fix Advice

[quantum_man]

I've had my Volvo 850 T5 for about a year and it's been leaking oil since I bought it! I have replaced the rear main oil seal (got a Volvo specialist to do this while they replaced the clutch), front and rear cam seals also done but there's still some leakage from the back of the engine. I think I might have a crack at replacing the turbo return pipe and oil seals, but could do with some advice with going about this. Could anyone offer advice on what I need to buy from Volvo and is this job possible without taking the engine out?

Also got signs of oil in the coolant tank, so could possibly need a new head gasket. I think this is liquid gasket, again any advice on how difficult this is to replace?

I'm confident in taking the inlet manifold off and have taken vairous bits off to clean / replace (such as the breather system), to give an idea of my mechanical ability! Not expert but prepared to give things a go.

Any advice would be appreciated!