Walikum as salam,
Do you mean a pension scheme for your limited company OR a personal private pension scheme?
Assuming you are looking for a personal pension scheme, the reason AJ seems to be popular here is that it appears to be offering the most number of shariah-compliant funds as a DIY option.
you may want to read this thread on Financial Education: Investment TIPS for Absolute Beginners - video 5 talks about SIPPS.
If you do want a readymade solution then I am sure @Abul_Fazal from Wahed maybe able to help.
May Allah guide you.