Public service pension transfer query

Any PS Pension experts out there?

I left one PS organisation 10 years ago .. took my pension lump sum but hold a preserved pension.
Joined another PS organisation immediately (no break in service)

Now I know pension transfer between the organisations can happen as I know a few who have done this.

I now wish to transfer my pension (bit late I know..) but am getting roadblocks  as I took my pension lump sum on leaving organisation1.

I've heard I could either 1. pay back my pension lump sum including interest (costly but doable) or 2. transfer pension but be entitled to lump sum based on ACTUAL service in organisation2 (monthly pension combined but lump only due for years worked in org2)

Any experience in this ???

No expert but puzzled by your query. You say you took your 'pension lump sum' but hold a 'preserved pension'. How long were you working in PS organisation no1? If less than 2 years, you may have actually received a refund of your superannuation contributions, less 25% tax. If so, to have that service calculated, you will be able to do so on payment of the appropriate superann, with interest, between now and retirement of on retirement.

Otherwise, I don't understand how it would work.