Connecting toilet help

[Mr Rotavator]

Hello.
I need to connect wc and sink waste to soil pipe inside vanity unit but have a few issues
1 limited space for flexi pan connector
2 toilet poor shape so pushes connectors off
3 vanity unit against an already tiled bath

Can I drill and attach a strap boss to elbow?
Or, trim elbow by 30-40mm to fit this? McAlpine WC-CON1V Rigid WC Connector White 110mm - https://www.NoLinkingToThis/p/mcalpine-wc-con1v-rigid-wc-connector-white-110mm/862hr

Any other solutions?

 

[Ben-gee]

No to strap boss on elbow.
Yes to trim back elbow slightly ( as little as possible).