How to install a toilet that fits properly?

The compression fitting just looks like a flexible hose hanging loose on the floor from the float valve. Another pic shows the toilet cold feed coming out of the wall. I don't think thats the problem.

 

It's not - the problem is that there is only an inch or so from the pan to the edge of the soil pipe. Sospan was just using the connector as a way of scaling the dimension (had me confused at first too!)

 

Ah! That's wot I didn't understand!

It looks as tho' it could move back the best part of a couple on inches, tho', and I don;t think the OP really wants much more than this?

Anyhoo, I think the situation's been answered well on this thread - Homebase are limited as to their options, but what they've done is simply not good enough.

Either sort it as the OP wants, or remove and refund and let him find an alternative.

 

Could be an interesting situation - "yes sir no problem heres your refund, we will send someone round in an hour to take away the toilet" Obviously Homebase aren't that sort of company but I could imagine others would be

 

Give me strength

 

The real problem Homebase made here was accepting an order they could not possible fulfill then trying to blag their way through the resulting mess.
In fact I think it would be acceptable to have the unit higher than the sill, and you have to weigh this against the difficulty and cost of trying to find one that is lower.
But whatever decision you come to, the horrible construction behind the toilet needs to be removed and rebuilt so it is at least the right size! That would instantly cure any issues with "gaps".