Possible to tune German Channels into Sky platform?

It's a seriously bad idea to try moving a Sky Dish. The bolts etc are really for one-time adjustment.

Since ages ago the SW was updated on Sky boxes such that they are very unhappy if they can't see the "Default Sky Transponder".

The OP needs an 78cm triax dish and a FTA receiver.

You can use a single dish with multi-feed and have Sky box and FTA receiver.
See http://www.techtir.ie/saortv/freesat
If the LNB for Sky is a Quad, you can add a Diseqc switch and have 28E & 19E on the FTA box as well as Sky on the Sky box.

Really that's a terrible recommendation:
1) You have practice. Most people if they even manage to loosen the bolts will end up with nothing.
2) Your sky mount may be un-usually un-rusted, or free from frequent moving. Or you are genius with a spanner.
3) Your Sky box may not have had more recent updates.
4) You must be great at ladders and DIY.

My experience and recommendation of use of Sky Box for over 10 years and 30 years of experience with Dishes, mounts and alignment is that NO-ONE should consider at all such an experiment unless it's an entirely spare dish and they don't need the Dish + Skybox for Freesat/UK TV/Sky and have a lot of time and patience.

You may find it fine, but it's irresponsible to suggest it's easy, straight forward or a reasonable option. Yes it might be possible, but it's stupid.

Also not all channels are equally strong. Foot print drops rapidly across UK and faster across Ireland. A Sky dish is too small in rain.

19E is served by four different Satellites: Astra 1H/1KR/1L/1M

Note all footprints are optimistic and further west (i.e. Anywhere in Ireland) the Elevation makes rain attenuation worse.
http://www.ses-astra.com/business/en/support/media-library/Footprint-Graphics/Footprint-Graphics-19-2-East/astra-1KR.php
http://www.ses-astra.com/business/en/support/media-library/Footprint-Graphics/Footprint-Graphics-19-2-East/astra-1M-European.php
http://www.ses-astra.com/business/en/support/media-library/Footprint-Graphics/Footprint-Graphics-19-2-East/astra-1L-FSS.php
http://www.ses-astra.com/business/en/support/media-library/Footprint-Graphics/Footprint-Graphics-19-2-East/astra-1M-Widebeam.php
Worst is http://www.ses-astra.com/business/en/support/media-library/Footprint-Graphics/Footprint-Graphics-19-2-East/astra-1H.php

Note how far off we are on centre of footprints.

Also not all transponders run full power. Footprints are Full power.
Reception Quality (Dish Size) is also affected by Transponder width in MHz / Symbol Rate, FEC and on DVB-S2 the modulation setting

It's likely a 65cm Sky dish would be OK on East side of Ireland. But unless it's a ONCE OFF move anyone would be mad to move their Sky dish.

For Multiple Feeds you always need a bigger dish as the LNB off axis from arm is always poorer signal.

A Triax TD78 with bar good for 28E 19E, 13E, 9E in East (28, 23.5, 19, 16 or 28, 19, 16, 13 also possible using some skinny Alps LNBFs that allow 3 degree spacing)

90/95cm in MidWest
110cm Extreme North West/South West
If someone wants Freesat / Sky and Continental they need either a Multifeed (multiple receivers, Sky sub and PVRs possible) or a Motorised system (single Tuner) for 42E to 45W
90/95 cm Triax Dish and Triax Adaptor Bar 6km west of Limerick City. The edge of dish in photo is 110cm Triax with Motek SG2100 motor for 42E to 45W.

A Sky dish and box is for Sky. A total waste of effort to try and use it for 19E. Even a fairly rubbish €70 B&Q kit is a better idea.

I did have a sky dish installed of my own when Sky 1st officially did Irish Digital Subs. About 4 years ago I wire brushed it and two coats of smooth Hammerite and installed it an old Sky box for a friend who only wanted UK FTA.

Yes, absolutely possible. But lots of people read the Forum. I just didn't want people reading thinking possible = good idea

You're not wasting bandwidth and it may be appropriate for someone to experiment having read the caveats.