Why don't you simply switch the Y and Z keys. (On youtube are tutorials for removing the black plastic keys and switching them) That is the one major difference. Although the funny thing is that if you are used to it quertz is better for English than for German and vice versa. Z is more important in German than y and in English it is the other way around. Those layouts are stupid for a reason but now we are used to it

.
English is way better for programming though.
You'd only have to remember all the special characters that replace the Umlaute and all the special characters at different Positions.
In theory if you switch to a UK Layout they might only have to switch the keyboard as this is has the same amount of keys. US keyboards are missing one key. I would always go for the UK if possible. I learned typing on the US and I still prefer the L shaped Enter you can just hit it more Enter like. It has more of a carriage return feeling than the US enter that looks like the shift key. And US keyboards do a worse job at different languages.
It is also possible to get single black keys on ebay to switch them around but they usually demand something in the neighborhood of 5 /$ for one tiny flimsy black plastic piece. To make the switch to a UK layout it takes 16-17 new keys according to my calculation. The 3 and 2 I would leave unchanged and some keys just have to move to a new position.
That would be 80 or $ unless you can find a cheaper source. If you do let me know. I also have the German keyboard but more because of resale value. I would like some more porgramming oriented UK one.