Monocock - The Low Level Route really is simple. The easiest way to go about things is to fly to Ashcroft Farm airfield's overhead and then fly a track of 360 not above 1250ft on the Manchester QNH. Once you reach the Thelwall Viaduct VRP take up a track of roughly 060 which will lead you to Barton. No need for any clearances to enter the corridor, although Manchester Appr on 119.525 will provide a FIS if you want.
Manchester ATC have produced a really useful guide to the route which is available for download off the
Barton Aerodrome website, direct link
here
Look forward to seeing you over Christmas